This series adds the kernel's build ID[1] to the stacktrace header
printed in oops messages, warnings, etc. and the build ID for any module
that appears in the stacktrace after the module name. The goal is to
make the stacktrace more self-contained and descriptive by including the
relevant build IDs in the kernel logs when something goes wrong. This
can be used by post processing tools like script/decode_stacktrace.sh
and kernel developers to easily locate the debug info associated with a
kernel crash and line up what line and file things started falling apart
at.
To show how this can be used I've included a patch to
decode_stacktrace.sh that downloads the debuginfo from a debuginfod
server. This also includes some patches to make the buildid.c file use
more const arguments and consolidate logic into buildid.c from kdump.
These are left to the end as they were mostly cleanup patches.
I don't know who exactly maintains this so I guess Andrew is the best
option to merge all this code. Otherwise, Petr mentioned it could
possibly go through the printk tree given that it touches mostly printk
things.
Here's an example lkdtm stacktrace on arm64.
WARNING: CPU: 4 PID: 3255 at drivers/misc/lkdtm/bugs.c:83 lkdtm_WARNING+0x28/0x30 [lkdtm]
Modules linked in: lkdtm rfcomm algif_hash algif_skcipher af_alg xt_cgroup uinput xt_MASQUERADE
CPU: 4 PID: 3255 Comm: bash Not tainted 5.11 #3 aa23f7a1231c229de205662d5a9e0d4c580f19a1
Hardware name: Google Lazor (rev3+) with KB Backlight (DT)
pstate: 00400009 (nzcv daif +PAN -UAO -TCO BTYPE=--)
pc : lkdtm_WARNING+0x28/0x30 [lkdtm]
lr : lkdtm_do_action+0x24/0x40 [lkdtm]
sp : ffffffc0134fbca0
x29: ffffffc0134fbca0 x28: ffffff92d53ba240
x27: 0000000000000000 x26: 0000000000000000
x25: 0000000000000000 x24: ffffffe3622352c0
x23: 0000000000000020 x22: ffffffe362233366
x21: ffffffe3622352e0 x20: ffffffc0134fbde0
x19: 0000000000000008 x18: 0000000000000000
x17: ffffff929b6536fc x16: 0000000000000000
x15: 0000000000000000 x14: 0000000000000012
x13: ffffffe380ed892c x12: ffffffe381d05068
x11: 0000000000000000 x10: 0000000000000000
x9 : 0000000000000001 x8 : ffffffe362237000
x7 : aaaaaaaaaaaaaaaa x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001
x3 : 0000000000000008 x2 : ffffff93fef25a70
x1 : ffffff93fef15788 x0 : ffffffe3622352e0
Call trace:
lkdtm_WARNING+0x28/0x30 [lkdtm ed5019fdf5e53be37cb1ba7899292d7e143b259e]
direct_entry+0x16c/0x1b4 [lkdtm ed5019fdf5e53be37cb1ba7899292d7e143b259e]
full_proxy_write+0x74/0xa4
vfs_write+0xec/0x2e8
ksys_write+0x84/0xf0
__arm64_sys_write+0x24/0x30
el0_svc_common+0xf4/0x1c0
do_el0_svc_compat+0x28/0x3c
el0_svc_compat+0x10/0x1c
el0_sync_compat_handler+0xa8/0xcc
el0_sync_compat+0x178/0x180
---[ end trace 3d95032303e59e68 ]---
Changes from v5 (https://lore.kernel.org/r/[email protected]):
* Rebased onto v5.12
* Moved logic for when to include build ID code to kdump patch
* Simplified commit text to show before/after details
Changes from v4 (https://lore.kernel.org/r/[email protected]):
* Stubbed out more code when CONFIG_STACKTRACE_BUILD_ID=n
* Use static_assert instead of BUILD_BUG_ON()
* Dropped bad printk change to IP on x86
Changes from v3 (https://lore.kernel.org/r/[email protected]):
* Fixed compilation warnings due to config changes
* Fixed kernel-doc on init_vmlinx_build_id()
* Totally removed add_build_id_vmcoreinfo()
* Added another printk format %pBb to help x86 print backtraces
* Some BUILD_BUG_ON() checks to make sure the buildid doesn't get bigger or smaller
Changes from v2 (https://lore.kernel.org/r/[email protected]):
* Renamed symbol printing function to indicate build IDness
* Put build ID information behind Kconfig knob
* Build ID for vmlinux is calculated in early init instead of on demand
* printk format is %pS[R]b
Changes from v1 (https://lore.kernel.org/r/[email protected]):
* New printk format %pSb and %pSr
* Return binary format instead of hex format string from build ID APIs
* Some new patches to cleanup buildid/decode_stacktrace.sh
* A new patch to decode_stacktrace.sh to parse output
[1] https://fedoraproject.org/wiki/Releases/FeatureBuildId
Cc: Alexei Starovoitov <[email protected]>
Cc: Andy Shevchenko <[email protected]>
Cc: Baoquan He <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Dave Young <[email protected]>
Cc: Evan Green <[email protected]>
Cc: Hsin-Yi Wang <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jessica Yu <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: <[email protected]>
Cc: Konstantin Khlebnikov <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: Rasmus Villemoes <[email protected]>
Cc: Sasha Levin <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vivek Goyal <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: peter enderborg <[email protected]>
Stephen Boyd (13):
buildid: Only consider GNU notes for build ID parsing
buildid: Add API to parse build ID out of buffer
buildid: Stash away kernels build ID on init
dump_stack: Add vmlinux build ID to stack traces
module: Add printk formats to add module build ID to stacktraces
arm64: stacktrace: Use %pSb for backtrace printing
x86/dumpstack: Use %pSb/%pBb for backtrace printing
scripts/decode_stacktrace.sh: Support debuginfod
scripts/decode_stacktrace.sh: Silence stderr messages from
addr2line/nm
scripts/decode_stacktrace.sh: Indicate 'auto' can be used for base
path
buildid: Mark some arguments const
buildid: Fix kernel-doc notation
kdump: Use vmlinux_build_id to simplify
Documentation/core-api/printk-formats.rst | 11 +++
arch/arm64/kernel/stacktrace.c | 2 +-
arch/x86/kernel/dumpstack.c | 2 +-
include/linux/buildid.h | 8 ++
include/linux/crash_core.h | 12 +--
include/linux/kallsyms.h | 20 ++++-
include/linux/module.h | 8 +-
init/main.c | 1 +
kernel/crash_core.c | 50 +----------
kernel/kallsyms.c | 101 +++++++++++++++++-----
kernel/module.c | 31 ++++++-
lib/Kconfig.debug | 11 +++
lib/buildid.c | 74 ++++++++++++----
lib/dump_stack.c | 13 ++-
lib/vsprintf.c | 8 +-
scripts/decode_stacktrace.sh | 89 +++++++++++++++----
16 files changed, 327 insertions(+), 114 deletions(-)
base-commit: 9f4ad9e425a1d3b6a34617b8ea226d56a119a717
--
https://chromeos.dev
Add an API that can parse the build ID out of a buffer, instead of a
vma, to support printing a kernel module's build ID for stack traces.
Cc: Jiri Olsa <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Jessica Yu <[email protected]>
Cc: Evan Green <[email protected]>
Cc: Hsin-Yi Wang <[email protected]>
Signed-off-by: Stephen Boyd <[email protected]>
---
include/linux/buildid.h | 1 +
lib/buildid.c | 50 ++++++++++++++++++++++++++++++-----------
2 files changed, 38 insertions(+), 13 deletions(-)
diff --git a/include/linux/buildid.h b/include/linux/buildid.h
index 40232f90db6e..ebce93f26d06 100644
--- a/include/linux/buildid.h
+++ b/include/linux/buildid.h
@@ -8,5 +8,6 @@
int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id,
__u32 *size);
+int build_id_parse_buf(const void *buf, unsigned char *build_id, u32 buf_size);
#endif
diff --git a/lib/buildid.c b/lib/buildid.c
index e014636ec3eb..6aea1c4e5e85 100644
--- a/lib/buildid.c
+++ b/lib/buildid.c
@@ -2,30 +2,23 @@
#include <linux/buildid.h>
#include <linux/elf.h>
+#include <linux/kernel.h>
#include <linux/pagemap.h>
#define BUILD_ID 3
+
/*
* Parse build id from the note segment. This logic can be shared between
* 32-bit and 64-bit system, because Elf32_Nhdr and Elf64_Nhdr are
* identical.
*/
-static inline int parse_build_id(void *page_addr,
- unsigned char *build_id,
- __u32 *size,
- void *note_start,
- Elf32_Word note_size)
+static int parse_build_id_buf(unsigned char *build_id,
+ __u32 *size,
+ const void *note_start,
+ Elf32_Word note_size)
{
Elf32_Word note_offs = 0, new_offs;
- /* check for overflow */
- if (note_start < page_addr || note_start + note_size < note_start)
- return -EINVAL;
-
- /* only supports note that fits in the first page */
- if (note_start + note_size > page_addr + PAGE_SIZE)
- return -EINVAL;
-
while (note_offs + sizeof(Elf32_Nhdr) < note_size) {
Elf32_Nhdr *nhdr = (Elf32_Nhdr *)(note_start + note_offs);
@@ -50,9 +43,27 @@ static inline int parse_build_id(void *page_addr,
break;
note_offs = new_offs;
}
+
return -EINVAL;
}
+static inline int parse_build_id(void *page_addr,
+ unsigned char *build_id,
+ __u32 *size,
+ void *note_start,
+ Elf32_Word note_size)
+{
+ /* check for overflow */
+ if (note_start < page_addr || note_start + note_size < note_start)
+ return -EINVAL;
+
+ /* only supports note that fits in the first page */
+ if (note_start + note_size > page_addr + PAGE_SIZE)
+ return -EINVAL;
+
+ return parse_build_id_buf(build_id, size, note_start, note_size);
+}
+
/* Parse build ID from 32-bit ELF */
static int get_build_id_32(void *page_addr, unsigned char *build_id,
__u32 *size)
@@ -148,3 +159,16 @@ int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id,
put_page(page);
return ret;
}
+
+/**
+ * build_id_parse_buf - Get build ID from a buffer
+ * @buf: Elf note section(s) to parse
+ * @buf_size: Size of @buf in bytes
+ * @build_id: Build ID parsed from @buf, at least BUILD_ID_SIZE_MAX long
+ *
+ * Return: 0 on success, -EINVAL otherwise
+ */
+int build_id_parse_buf(const void *buf, unsigned char *build_id, u32 buf_size)
+{
+ return parse_build_id_buf(build_id, NULL, buf, buf_size);
+}
--
https://chromeos.dev
Parse the kernel's build ID at initialization so that other code can
print a hex format string representation of the running kernel's build
ID. This will be used in the kdump and dump_stack code so that
developers can easily locate the vmlinux debug symbols for a
crash/stacktrace.
Cc: Jiri Olsa <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Jessica Yu <[email protected]>
Cc: Evan Green <[email protected]>
Cc: Hsin-Yi Wang <[email protected]>
Cc: Dave Young <[email protected]>
Acked-by: Baoquan He <[email protected]>
Cc: Vivek Goyal <[email protected]>
Cc: <[email protected]>
Signed-off-by: Stephen Boyd <[email protected]>
---
include/linux/buildid.h | 3 +++
init/main.c | 1 +
lib/buildid.c | 15 +++++++++++++++
3 files changed, 19 insertions(+)
diff --git a/include/linux/buildid.h b/include/linux/buildid.h
index ebce93f26d06..f375900cf9ed 100644
--- a/include/linux/buildid.h
+++ b/include/linux/buildid.h
@@ -10,4 +10,7 @@ int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id,
__u32 *size);
int build_id_parse_buf(const void *buf, unsigned char *build_id, u32 buf_size);
+extern unsigned char vmlinux_build_id[BUILD_ID_SIZE_MAX];
+void init_vmlinux_build_id(void);
+
#endif
diff --git a/init/main.c b/init/main.c
index 53b278845b88..eaede2f41327 100644
--- a/init/main.c
+++ b/init/main.c
@@ -857,6 +857,7 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void)
set_task_stack_end_magic(&init_task);
smp_setup_processor_id();
debug_objects_early_init();
+ init_vmlinux_build_id();
cgroup_init_early();
diff --git a/lib/buildid.c b/lib/buildid.c
index 6aea1c4e5e85..1103ed46214f 100644
--- a/lib/buildid.c
+++ b/lib/buildid.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/buildid.h>
+#include <linux/cache.h>
#include <linux/elf.h>
#include <linux/kernel.h>
#include <linux/pagemap.h>
@@ -172,3 +173,17 @@ int build_id_parse_buf(const void *buf, unsigned char *build_id, u32 buf_size)
{
return parse_build_id_buf(build_id, NULL, buf, buf_size);
}
+
+unsigned char vmlinux_build_id[BUILD_ID_SIZE_MAX] __ro_after_init;
+
+/**
+ * init_vmlinux_build_id - Compute and stash the running kernel's build ID
+ */
+void __init init_vmlinux_build_id(void)
+{
+ extern const void __start_notes __weak;
+ extern const void __stop_notes __weak;
+ unsigned int size = &__stop_notes - &__start_notes;
+
+ build_id_parse_buf(&__start_notes, vmlinux_build_id, size);
+}
--
https://chromeos.dev
Add the running kernel's build ID[1] to the stacktrace information
header. This makes it simpler for developers to locate the vmlinux with
full debuginfo for a particular kernel stacktrace. Combined with
scripts/decode_stracktrace.sh, a developer can download the correct
vmlinux from a debuginfod[2] server and find the exact file and line
number for the functions plus offsets in a stacktrace.
This is especially useful for pstore crash debugging where the kernel
crashes are recorded in the pstore logs and the recovery kernel is
different or the debuginfo doesn't exist on the device due to space
concerns (the data can be large and a security concern). The stacktrace
can be analyzed after the crash by using the build ID to find the
matching vmlinux and understand where in the function something went
wrong.
Example stacktrace from lkdtm:
WARNING: CPU: 4 PID: 3255 at drivers/misc/lkdtm/bugs.c:83 lkdtm_WARNING+0x28/0x30 [lkdtm]
Modules linked in: lkdtm rfcomm algif_hash algif_skcipher af_alg xt_cgroup uinput xt_MASQUERADE
CPU: 4 PID: 3255 Comm: bash Not tainted 5.11 #3 aa23f7a1231c229de205662d5a9e0d4c580f19a1
Hardware name: Google Lazor (rev3+) with KB Backlight (DT)
pstate: 00400009 (nzcv daif +PAN -UAO -TCO BTYPE=--)
pc : lkdtm_WARNING+0x28/0x30 [lkdtm]
The hex string aa23f7a1231c229de205662d5a9e0d4c580f19a1 is the build ID,
following the kernel version number. Put it all behind a config option,
STACKTRACE_BUILD_ID, so that kernel developers can remove this
information if they decide it is too much.
Cc: Jiri Olsa <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Jessica Yu <[email protected]>
Cc: Evan Green <[email protected]>
Cc: Hsin-Yi Wang <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Andy Shevchenko <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Link: https://fedoraproject.org/wiki/Releases/FeatureBuildId [1]
Link: https://sourceware.org/elfutils/Debuginfod.html [2]
Signed-off-by: Stephen Boyd <[email protected]>
---
include/linux/buildid.h | 4 ++++
lib/Kconfig.debug | 11 +++++++++++
lib/buildid.c | 2 ++
lib/dump_stack.c | 13 +++++++++++--
4 files changed, 28 insertions(+), 2 deletions(-)
diff --git a/include/linux/buildid.h b/include/linux/buildid.h
index f375900cf9ed..3e8d77a93ec4 100644
--- a/include/linux/buildid.h
+++ b/include/linux/buildid.h
@@ -10,7 +10,11 @@ int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id,
__u32 *size);
int build_id_parse_buf(const void *buf, unsigned char *build_id, u32 buf_size);
+#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
extern unsigned char vmlinux_build_id[BUILD_ID_SIZE_MAX];
void init_vmlinux_build_id(void);
+#else
+static inline void init_vmlinux_build_id(void) { }
+#endif
#endif
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 417c3d3e521b..aa6d8e528879 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -35,6 +35,17 @@ config PRINTK_CALLER
no option to enable/disable at the kernel command line parameter or
sysfs interface.
+config STACKTRACE_BUILD_ID
+ bool "Show build ID information in stacktraces"
+ depends on PRINTK
+ help
+ Selecting this option adds build ID information for symbols in
+ stacktraces printed with the printk format '%p[SR]b'.
+
+ This option is intended for distros where debuginfo is not easily
+ accessible but can be downloaded given the build ID of the vmlinux or
+ kernel module where the function is located.
+
config CONSOLE_LOGLEVEL_DEFAULT
int "Default console loglevel (1-15)"
range 1 15
diff --git a/lib/buildid.c b/lib/buildid.c
index 1103ed46214f..6f1e2903740b 100644
--- a/lib/buildid.c
+++ b/lib/buildid.c
@@ -174,6 +174,7 @@ int build_id_parse_buf(const void *buf, unsigned char *build_id, u32 buf_size)
return parse_build_id_buf(build_id, NULL, buf, buf_size);
}
+#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
unsigned char vmlinux_build_id[BUILD_ID_SIZE_MAX] __ro_after_init;
/**
@@ -187,3 +188,4 @@ void __init init_vmlinux_build_id(void)
build_id_parse_buf(&__start_notes, vmlinux_build_id, size);
}
+#endif
diff --git a/lib/dump_stack.c b/lib/dump_stack.c
index f5a33b6f773f..d685331b065f 100644
--- a/lib/dump_stack.c
+++ b/lib/dump_stack.c
@@ -5,6 +5,7 @@
*/
#include <linux/kernel.h>
+#include <linux/buildid.h>
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
@@ -36,6 +37,14 @@ void __init dump_stack_set_arch_desc(const char *fmt, ...)
va_end(args);
}
+#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
+#define BUILD_ID_FMT " %20phN"
+#define BUILD_ID_VAL vmlinux_build_id
+#else
+#define BUILD_ID_FMT "%s"
+#define BUILD_ID_VAL ""
+#endif
+
/**
* dump_stack_print_info - print generic debug info for dump_stack()
* @log_lvl: log level
@@ -45,13 +54,13 @@ void __init dump_stack_set_arch_desc(const char *fmt, ...)
*/
void dump_stack_print_info(const char *log_lvl)
{
- printk("%sCPU: %d PID: %d Comm: %.20s %s%s %s %.*s\n",
+ printk("%sCPU: %d PID: %d Comm: %.20s %s%s %s %.*s" BUILD_ID_FMT "\n",
log_lvl, raw_smp_processor_id(), current->pid, current->comm,
kexec_crash_loaded() ? "Kdump: loaded " : "",
print_tainted(),
init_utsname()->release,
(int)strcspn(init_utsname()->version, " "),
- init_utsname()->version);
+ init_utsname()->version, BUILD_ID_VAL);
if (dump_stack_arch_desc_str[0] != '\0')
printk("%sHardware name: %s\n",
--
https://chromeos.dev
Let's make kernel stacktraces easier to identify by including the build
ID[1] of a module if the stacktrace is printing a symbol from a module.
This makes it simpler for developers to locate a kernel module's full
debuginfo for a particular stacktrace. Combined with
scripts/decode_stracktrace.sh, a developer can download the matching
debuginfo from a debuginfod[2] server and find the exact file and line
number for the functions plus offsets in a stacktrace that match the
module. This is especially useful for pstore crash debugging where the
kernel crashes are recorded in something like console-ramoops and the
recovery kernel/modules are different or the debuginfo doesn't exist on
the device due to space concerns (the debuginfo can be too large for
space limited devices).
Originally, I put this on the %pS format, but that was quickly rejected
given that %pS is used in other places such as ftrace where build IDs
aren't meaningful. There was some discussions on the list to put every
module build ID into the "Modules linked in:" section of the stacktrace
message but that quickly becomes very hard to read once you have more
than three or four modules linked in. It also provides too much
information when we don't expect each module to be traversed in a
stacktrace. Having the build ID for modules that aren't important just
makes things messy. Splitting it to multiple lines for each module
quickly explodes the number of lines printed in an oops too, possibly
wrapping the warning off the console. And finally, trying to stash away
each module used in a callstack to provide the ID of each symbol printed
is cumbersome and would require changes to each architecture to stash
away modules and return their build IDs once unwinding has completed.
Instead, we opt for the simpler approach of introducing new printk
formats '%pS[R]b' for "pointer symbolic backtrace with module build ID"
and '%pBb' for "pointer backtrace with module build ID" and then
updating the few places in the architecture layer where the stacktrace
is printed to use this new format.
Before:
Call trace:
lkdtm_WARNING+0x28/0x30 [lkdtm]
direct_entry+0x16c/0x1b4 [lkdtm]
full_proxy_write+0x74/0xa4
vfs_write+0xec/0x2e8
After:
Call trace:
lkdtm_WARNING+0x28/0x30 [lkdtm 6c2215028606bda50de823490723dc4bc5bf46f9]
direct_entry+0x16c/0x1b4 [lkdtm 6c2215028606bda50de823490723dc4bc5bf46f9]
full_proxy_write+0x74/0xa4
vfs_write+0xec/0x2e8
Cc: Jiri Olsa <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Jessica Yu <[email protected]>
Cc: Evan Green <[email protected]>
Cc: Hsin-Yi Wang <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: Andy Shevchenko <[email protected]>
Cc: Rasmus Villemoes <[email protected]>
Cc: <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Link: https://fedoraproject.org/wiki/Releases/FeatureBuildId [1]
Link: https://sourceware.org/elfutils/Debuginfod.html [2]
Signed-off-by: Stephen Boyd <[email protected]>
---
Documentation/core-api/printk-formats.rst | 11 +++
include/linux/kallsyms.h | 20 ++++-
include/linux/module.h | 8 +-
kernel/kallsyms.c | 101 +++++++++++++++++-----
kernel/module.c | 31 ++++++-
lib/vsprintf.c | 8 +-
6 files changed, 154 insertions(+), 25 deletions(-)
diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst
index 160e710d992f..5f60533f2a56 100644
--- a/Documentation/core-api/printk-formats.rst
+++ b/Documentation/core-api/printk-formats.rst
@@ -114,6 +114,17 @@ used when printing stack backtraces. The specifier takes into
consideration the effect of compiler optimisations which may occur
when tail-calls are used and marked with the noreturn GCC attribute.
+If the pointer is within a module, the module name and optionally build ID is
+printed after the symbol name with an extra ``b`` appended to the end of the
+specifier.
+
+::
+ %pS versatile_init+0x0/0x110 [module_name]
+ %pSb versatile_init+0x0/0x110 [module_name ed5019fdf5e53be37cb1ba7899292d7e143b259e]
+ %pSRb versatile_init+0x9/0x110 [module_name ed5019fdf5e53be37cb1ba7899292d7e143b259e]
+ (with __builtin_extract_return_addr() translation)
+ %pBb prev_fn_of_versatile_init+0x88/0x88 [module_name ed5019fdf5e53be37cb1ba7899292d7e143b259e]
+
Probed Pointers from BPF / tracing
----------------------------------
diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
index 465060acc981..f760cb839775 100644
--- a/include/linux/kallsyms.h
+++ b/include/linux/kallsyms.h
@@ -7,6 +7,7 @@
#define _LINUX_KALLSYMS_H
#include <linux/errno.h>
+#include <linux/buildid.h>
#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/mm.h>
@@ -15,8 +16,9 @@
#include <asm/sections.h>
#define KSYM_NAME_LEN 128
-#define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s]") + (KSYM_NAME_LEN - 1) + \
- 2*(BITS_PER_LONG*3/10) + (MODULE_NAME_LEN - 1) + 1)
+#define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s %s]") + (KSYM_NAME_LEN - 1) + \
+ 2*(BITS_PER_LONG*3/10) + (MODULE_NAME_LEN - 1) + \
+ (BUILD_ID_SIZE_MAX * 2) + 1)
struct cred;
struct module;
@@ -91,8 +93,10 @@ const char *kallsyms_lookup(unsigned long addr,
/* Look up a kernel symbol and return it in a text buffer. */
extern int sprint_symbol(char *buffer, unsigned long address);
+extern int sprint_symbol_build_id(char *buffer, unsigned long address);
extern int sprint_symbol_no_offset(char *buffer, unsigned long address);
extern int sprint_backtrace(char *buffer, unsigned long address);
+extern int sprint_backtrace_build_id(char *buffer, unsigned long address);
int lookup_symbol_name(unsigned long addr, char *symname);
int lookup_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name);
@@ -128,6 +132,12 @@ static inline int sprint_symbol(char *buffer, unsigned long addr)
return 0;
}
+static inline int sprint_symbol_build_id(char *buffer, unsigned long address)
+{
+ *buffer = '\0';
+ return 0;
+}
+
static inline int sprint_symbol_no_offset(char *buffer, unsigned long addr)
{
*buffer = '\0';
@@ -140,6 +150,12 @@ static inline int sprint_backtrace(char *buffer, unsigned long addr)
return 0;
}
+static inline int sprint_backtrace_build_id(char *buffer, unsigned long addr)
+{
+ *buffer = '\0';
+ return 0;
+}
+
static inline int lookup_symbol_name(unsigned long addr, char *symname)
{
return -ERANGE;
diff --git a/include/linux/module.h b/include/linux/module.h
index da4b6fbe8ebe..4145a53ff9d8 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -11,6 +11,7 @@
#include <linux/list.h>
#include <linux/stat.h>
+#include <linux/buildid.h>
#include <linux/compiler.h>
#include <linux/cache.h>
#include <linux/kmod.h>
@@ -364,6 +365,11 @@ struct module {
/* Unique handle for this module */
char name[MODULE_NAME_LEN];
+#ifdef CONFIG_STACKTRACE_BUILD_ID
+ /* Module build ID */
+ unsigned char build_id[BUILD_ID_SIZE_MAX];
+#endif
+
/* Sysfs stuff. */
struct module_kobject mkobj;
struct module_attribute *modinfo_attrs;
@@ -627,7 +633,7 @@ void *dereference_module_function_descriptor(struct module *mod, void *ptr);
const char *module_address_lookup(unsigned long addr,
unsigned long *symbolsize,
unsigned long *offset,
- char **modname,
+ char **modname, const unsigned char **modbuildid,
char *namebuf);
int lookup_module_symbol_name(unsigned long addr, char *symname);
int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name);
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 8043a90aa50e..b1ad3df3d71b 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -25,7 +25,10 @@
#include <linux/filter.h>
#include <linux/ftrace.h>
#include <linux/kprobes.h>
+#include <linux/build_bug.h>
#include <linux/compiler.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
/*
* These will be re-linked against their real values
@@ -273,21 +276,13 @@ int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize,
get_symbol_pos(addr, symbolsize, offset);
return 1;
}
- return !!module_address_lookup(addr, symbolsize, offset, NULL, namebuf) ||
+ return !!module_address_lookup(addr, symbolsize, offset, NULL, NULL, namebuf) ||
!!__bpf_address_lookup(addr, symbolsize, offset, namebuf);
}
-/*
- * Lookup an address
- * - modname is set to NULL if it's in the kernel.
- * - We guarantee that the returned name is valid until we reschedule even if.
- * It resides in a module.
- * - We also guarantee that modname will be valid until rescheduled.
- */
-const char *kallsyms_lookup(unsigned long addr,
- unsigned long *symbolsize,
- unsigned long *offset,
- char **modname, char *namebuf)
+const char *kallsyms_lookup_buildid(unsigned long addr, unsigned long *symbolsize,
+ unsigned long *offset, char **modname,
+ const unsigned char **modbuildid, char *namebuf)
{
const char *ret;
@@ -303,12 +298,14 @@ const char *kallsyms_lookup(unsigned long addr,
namebuf, KSYM_NAME_LEN);
if (modname)
*modname = NULL;
+ if (modbuildid)
+ *modbuildid = NULL;
return namebuf;
}
/* See if it's in a module or a BPF JITed image. */
ret = module_address_lookup(addr, symbolsize, offset,
- modname, namebuf);
+ modname, modbuildid, namebuf);
if (!ret)
ret = bpf_address_lookup(addr, symbolsize,
offset, modname, namebuf);
@@ -319,6 +316,22 @@ const char *kallsyms_lookup(unsigned long addr,
return ret;
}
+/*
+ * Lookup an address
+ * - modname is set to NULL if it's in the kernel.
+ * - We guarantee that the returned name is valid until we reschedule even if.
+ * It resides in a module.
+ * - We also guarantee that modname will be valid until rescheduled.
+ */
+const char *kallsyms_lookup(unsigned long addr,
+ unsigned long *symbolsize,
+ unsigned long *offset,
+ char **modname, char *namebuf)
+{
+ return kallsyms_lookup_buildid(addr, symbolsize, offset, modname,
+ NULL, namebuf);
+}
+
int lookup_symbol_name(unsigned long addr, char *symname)
{
symname[0] = '\0';
@@ -359,15 +372,17 @@ int lookup_symbol_attrs(unsigned long addr, unsigned long *size,
/* Look up a kernel symbol and return it in a text buffer. */
static int __sprint_symbol(char *buffer, unsigned long address,
- int symbol_offset, int add_offset)
+ int symbol_offset, int add_offset, int add_buildid)
{
char *modname;
+ const unsigned char *buildid;
const char *name;
unsigned long offset, size;
int len;
address += symbol_offset;
- name = kallsyms_lookup(address, &size, &offset, &modname, buffer);
+ name = kallsyms_lookup_buildid(address, &size, &offset, &modname, &buildid,
+ buffer);
if (!name)
return sprintf(buffer, "0x%lx", address - symbol_offset);
@@ -379,8 +394,17 @@ static int __sprint_symbol(char *buffer, unsigned long address,
if (add_offset)
len += sprintf(buffer + len, "+%#lx/%#lx", offset, size);
- if (modname)
- len += sprintf(buffer + len, " [%s]", modname);
+ if (modname) {
+ len += sprintf(buffer + len, " [%s", modname);
+#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
+ if (add_buildid && buildid) {
+ /* build ID should match length of sprintf */
+ static_assert(sizeof(typeof_member(struct module, build_id)) == 20);
+ len += sprintf(buffer + len, " %20phN", buildid);
+ }
+#endif
+ len += sprintf(buffer + len, "]");
+ }
return len;
}
@@ -398,10 +422,27 @@ static int __sprint_symbol(char *buffer, unsigned long address,
*/
int sprint_symbol(char *buffer, unsigned long address)
{
- return __sprint_symbol(buffer, address, 0, 1);
+ return __sprint_symbol(buffer, address, 0, 1, 0);
}
EXPORT_SYMBOL_GPL(sprint_symbol);
+/**
+ * sprint_symbol_build_id - Look up a kernel symbol and return it in a text buffer
+ * @buffer: buffer to be stored
+ * @address: address to lookup
+ *
+ * This function looks up a kernel symbol with @address and stores its name,
+ * offset, size, module name and module build ID to @buffer if possible. If no
+ * symbol was found, just saves its @address as is.
+ *
+ * This function returns the number of bytes stored in @buffer.
+ */
+int sprint_symbol_build_id(char *buffer, unsigned long address)
+{
+ return __sprint_symbol(buffer, address, 0, 1, 1);
+}
+EXPORT_SYMBOL_GPL(sprint_symbol_build_id);
+
/**
* sprint_symbol_no_offset - Look up a kernel symbol and return it in a text buffer
* @buffer: buffer to be stored
@@ -415,7 +456,7 @@ EXPORT_SYMBOL_GPL(sprint_symbol);
*/
int sprint_symbol_no_offset(char *buffer, unsigned long address)
{
- return __sprint_symbol(buffer, address, 0, 0);
+ return __sprint_symbol(buffer, address, 0, 0, 0);
}
EXPORT_SYMBOL_GPL(sprint_symbol_no_offset);
@@ -435,7 +476,27 @@ EXPORT_SYMBOL_GPL(sprint_symbol_no_offset);
*/
int sprint_backtrace(char *buffer, unsigned long address)
{
- return __sprint_symbol(buffer, address, -1, 1);
+ return __sprint_symbol(buffer, address, -1, 1, 0);
+}
+
+/**
+ * sprint_backtrace_build_id - Look up a backtrace symbol and return it in a text buffer
+ * @buffer: buffer to be stored
+ * @address: address to lookup
+ *
+ * This function is for stack backtrace and does the same thing as
+ * sprint_symbol() but with modified/decreased @address. If there is a
+ * tail-call to the function marked "noreturn", gcc optimized out code after
+ * the call so that the stack-saved return address could point outside of the
+ * caller. This function ensures that kallsyms will find the original caller
+ * by decreasing @address. This function also appends the module build ID to
+ * the @buffer if @address is within a kernel module.
+ *
+ * This function returns the number of bytes stored in @buffer.
+ */
+int sprint_backtrace_build_id(char *buffer, unsigned long address)
+{
+ return __sprint_symbol(buffer, address, -1, 1, 1);
}
/* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
diff --git a/kernel/module.c b/kernel/module.c
index 30479355ab85..a5eaf5188a83 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -13,6 +13,7 @@
#include <linux/trace_events.h>
#include <linux/init.h>
#include <linux/kallsyms.h>
+#include <linux/buildid.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/sysfs.h>
@@ -2780,6 +2781,26 @@ static void add_kallsyms(struct module *mod, const struct load_info *info)
}
#endif /* CONFIG_KALLSYMS */
+#if IS_ENABLED(CONFIG_KALLSYMS) && IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
+static void init_build_id(struct module *mod, const struct load_info *info)
+{
+ const Elf_Shdr *sechdr;
+ unsigned int i;
+
+ for (i = 0; i < info->hdr->e_shnum; i++) {
+ sechdr = &info->sechdrs[i];
+ if (!sect_empty(sechdr) && sechdr->sh_type == SHT_NOTE &&
+ !build_id_parse_buf((void *)sechdr->sh_addr, mod->build_id,
+ sechdr->sh_size))
+ break;
+ }
+}
+#else
+static void init_build_id(struct module *mod, const struct load_info *info)
+{
+}
+#endif
+
static void dynamic_debug_setup(struct module *mod, struct _ddebug *debug, unsigned int num)
{
if (!debug)
@@ -4004,6 +4025,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
goto free_arch_cleanup;
}
+ init_build_id(mod, info);
dynamic_debug_setup(mod, info->debug, info->num_debug);
/* Ftrace init must be called in the MODULE_STATE_UNFORMED state */
@@ -4235,7 +4257,7 @@ void * __weak dereference_module_function_descriptor(struct module *mod,
const char *module_address_lookup(unsigned long addr,
unsigned long *size,
unsigned long *offset,
- char **modname,
+ char **modname, const unsigned char **modbuildid,
char *namebuf)
{
const char *ret = NULL;
@@ -4246,6 +4268,13 @@ const char *module_address_lookup(unsigned long addr,
if (mod) {
if (modname)
*modname = mod->name;
+ if (modbuildid) {
+#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
+ *modbuildid = mod->build_id;
+#else
+ *modbuildid = NULL;
+#endif
+ }
ret = find_kallsyms_symbol(mod, addr, size, offset);
}
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 41ddc353ebb8..fee5282ebb0a 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -966,8 +966,12 @@ char *symbol_string(char *buf, char *end, void *ptr,
value = (unsigned long)ptr;
#ifdef CONFIG_KALLSYMS
- if (*fmt == 'B')
+ if (*fmt == 'B' && fmt[1] == 'b')
+ sprint_backtrace_build_id(sym, value);
+ else if (*fmt == 'B')
sprint_backtrace(sym, value);
+ else if (*fmt == 'S' && (fmt[1] == 'b' || (fmt[1] == 'R' && fmt[2] == 'b')))
+ sprint_symbol_build_id(sym, value);
else if (*fmt != 's')
sprint_symbol(sym, value);
else
@@ -2129,9 +2133,11 @@ early_param("no_hash_pointers", no_hash_pointers_enable);
* - 'S' For symbolic direct pointers (or function descriptors) with offset
* - 's' For symbolic direct pointers (or function descriptors) without offset
* - '[Ss]R' as above with __builtin_extract_return_addr() translation
+ * - 'S[R]b' as above with module build ID (for use in backtraces)
* - '[Ff]' %pf and %pF were obsoleted and later removed in favor of
* %ps and %pS. Be careful when re-using these specifiers.
* - 'B' For backtraced symbolic direct pointers with offset
+ * - 'Bb' as above with module build ID (for use in backtraces)
* - 'R' For decoded struct resource, e.g., [mem 0x0-0x1f 64bit pref]
* - 'r' For raw struct resource, e.g., [mem 0x0-0x1f flags 0x201]
* - 'b[l]' For a bitmap, the number of bits is determined by the field
--
https://chromeos.dev
Let's use the new printk format to print the stacktrace entry when
printing a backtrace to the kernel logs. This will include any module's
build ID[1] in it so that offline/crash debugging can easily locate the
debuginfo for a module via something like debuginfod[2].
Acked-by: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Jessica Yu <[email protected]>
Cc: Evan Green <[email protected]>
Cc: Hsin-Yi Wang <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Andy Shevchenko <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Link: https://fedoraproject.org/wiki/Releases/FeatureBuildId [1]
Link: https://sourceware.org/elfutils/Debuginfod.html [2]
Signed-off-by: Stephen Boyd <[email protected]>
---
arch/arm64/kernel/stacktrace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index d55bdfb7789c..ddb64ada74c2 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -129,7 +129,7 @@ NOKPROBE_SYMBOL(walk_stackframe);
static void dump_backtrace_entry(unsigned long where, const char *loglvl)
{
- printk("%s %pS\n", loglvl, (void *)where);
+ printk("%s %pSb\n", loglvl, (void *)where);
}
void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
--
https://chromeos.dev
Now that stacktraces contain the build ID information we can update this
script to use debuginfod-find to locate the debuginfo for the vmlinux
and modules automatically. This can replace the existing code that
requires specifying a path to vmlinux or tries to find the vmlinux and
modules automatically by using the release number. Work it into the
script as a fallback option if the vmlinux isn't specified on the
commandline.
Cc: Jiri Olsa <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Jessica Yu <[email protected]>
Cc: Evan Green <[email protected]>
Cc: Hsin-Yi Wang <[email protected]>
Cc: Konstantin Khlebnikov <[email protected]>
Cc: Sasha Levin <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Andy Shevchenko <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Signed-off-by: Stephen Boyd <[email protected]>
---
scripts/decode_stacktrace.sh | 81 +++++++++++++++++++++++++++++++-----
1 file changed, 70 insertions(+), 11 deletions(-)
diff --git a/scripts/decode_stacktrace.sh b/scripts/decode_stacktrace.sh
index 90398347e366..ca21f8bdf5f2 100755
--- a/scripts/decode_stacktrace.sh
+++ b/scripts/decode_stacktrace.sh
@@ -3,11 +3,10 @@
# (c) 2014, Sasha Levin <[email protected]>
#set -x
-if [[ $# < 1 ]]; then
+usage() {
echo "Usage:"
echo " $0 -r <release> | <vmlinux> [base path] [modules path]"
- exit 1
-fi
+}
if [[ $1 == "-r" ]] ; then
vmlinux=""
@@ -24,6 +23,7 @@ if [[ $1 == "-r" ]] ; then
if [[ $vmlinux == "" ]] ; then
echo "ERROR! vmlinux image for release $release is not found" >&2
+ usage
exit 2
fi
else
@@ -31,12 +31,35 @@ else
basepath=${2-auto}
modpath=$3
release=""
+ debuginfod=
+
+ # Can we use debuginfod-find?
+ if type debuginfod-find >/dev/null 2>&1 ; then
+ debuginfod=${1-only}
+ fi
+
+ if [[ $vmlinux == "" && -z $debuginfod ]] ; then
+ echo "ERROR! vmlinux image must be specified" >&2
+ usage
+ exit 1
+ fi
fi
declare -A cache
declare -A modcache
find_module() {
+ if [[ -n $debuginfod ]] ; then
+ if [[ -n $modbuildid ]] ; then
+ debuginfod-find debuginfo $modbuildid && return
+ fi
+
+ # Only using debuginfod so don't try to find vmlinux module path
+ if [[ $debuginfod == "only" ]] ; then
+ return
+ fi
+ fi
+
if [[ "$modpath" != "" ]] ; then
for fn in $(find "$modpath" -name "${module//_/[-_]}.ko*") ; do
if readelf -WS "$fn" | grep -qwF .debug_line ; then
@@ -150,6 +173,27 @@ parse_symbol() {
symbol="$segment$name ($code)"
}
+debuginfod_get_vmlinux() {
+ local vmlinux_buildid=${1##* }
+
+ if [[ $vmlinux != "" ]]; then
+ return
+ fi
+
+ if [[ $vmlinux_buildid =~ ^[0-9a-f]+ ]]; then
+ vmlinux=$(debuginfod-find debuginfo $vmlinux_buildid)
+ if [[ $? -ne 0 ]] ; then
+ echo "ERROR! vmlinux image not found via debuginfod-find" >&2
+ usage
+ exit 2
+ fi
+ return
+ fi
+ echo "ERROR! Build ID for vmlinux not found. Try passing -r or specifying vmlinux" >&2
+ usage
+ exit 2
+}
+
decode_code() {
local scripts=`dirname "${BASH_SOURCE[0]}"`
@@ -157,6 +201,14 @@ decode_code() {
}
handle_line() {
+ if [[ $basepath == "auto" && $vmlinux != "" ]] ; then
+ module=""
+ symbol="kernel_init+0x0/0x0"
+ parse_symbol
+ basepath=${symbol#kernel_init (}
+ basepath=${basepath%/init/main.c:*)}
+ fi
+
local words
# Tokenize
@@ -182,16 +234,28 @@ handle_line() {
fi
done
+ if [[ ${words[$last]} =~ ^[0-9a-f]+\] ]]; then
+ words[$last-1]="${words[$last-1]} ${words[$last]}"
+ unset words[$last]
+ last=$(( $last - 1 ))
+ fi
+
if [[ ${words[$last]} =~ \[([^]]+)\] ]]; then
module=${words[$last]}
module=${module#\[}
module=${module%\]}
+ modbuildid=${module#* }
+ module=${module% *}
+ if [[ $modbuildid == $module ]]; then
+ modbuildid=
+ fi
symbol=${words[$last-1]}
unset words[$last-1]
else
# The symbol is the last element, process it
symbol=${words[$last]}
module=
+ modbuildid=
fi
unset words[$last]
@@ -201,14 +265,6 @@ handle_line() {
echo "${words[@]}" "$symbol $module"
}
-if [[ $basepath == "auto" ]] ; then
- module=""
- symbol="kernel_init+0x0/0x0"
- parse_symbol
- basepath=${symbol#kernel_init (}
- basepath=${basepath%/init/main.c:*)}
-fi
-
while read line; do
# Let's see if we have an address in the line
if [[ $line =~ \[\<([^]]+)\>\] ]] ||
@@ -218,6 +274,9 @@ while read line; do
# Is it a code line?
elif [[ $line == *Code:* ]]; then
decode_code "$line"
+ # Is it a version line?
+ elif [[ -n $debuginfod && $line =~ PID:\ [0-9]+\ Comm: ]]; then
+ debuginfod_get_vmlinux "$line"
else
# Nothing special in this line, show it as is
echo "$line"
--
https://chromeos.dev
Sometimes if you're using tools that have linked things improperly or
have new features/sections that older tools don't expect you'll see
warnings printed to stderr. We don't really care about these warnings,
so let's just silence these messages to cleanup output of this script.
Cc: Jiri Olsa <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Jessica Yu <[email protected]>
Cc: Evan Green <[email protected]>
Cc: Hsin-Yi Wang <[email protected]>
Cc: Konstantin Khlebnikov <[email protected]>
Cc: Sasha Levin <[email protected]>
Signed-off-by: Stephen Boyd <[email protected]>
---
scripts/decode_stacktrace.sh | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/scripts/decode_stacktrace.sh b/scripts/decode_stacktrace.sh
index ca21f8bdf5f2..20b5af1ebe5e 100755
--- a/scripts/decode_stacktrace.sh
+++ b/scripts/decode_stacktrace.sh
@@ -74,7 +74,7 @@ find_module() {
find_module && return
if [[ $release == "" ]] ; then
- release=$(gdb -ex 'print init_uts_ns.name.release' -ex 'quit' -quiet -batch "$vmlinux" | sed -n 's/\$1 = "\(.*\)".*/\1/p')
+ release=$(gdb -ex 'print init_uts_ns.name.release' -ex 'quit' -quiet -batch "$vmlinux" 2>/dev/null | sed -n 's/\$1 = "\(.*\)".*/\1/p')
fi
for dn in {/usr/lib/debug,}/lib/modules/$release ; do
@@ -128,7 +128,7 @@ parse_symbol() {
if [[ "${cache[$module,$name]+isset}" == "isset" ]]; then
local base_addr=${cache[$module,$name]}
else
- local base_addr=$(nm "$objfile" | awk '$3 == "'$name'" && ($2 == "t" || $2 == "T") {print $1; exit}')
+ local base_addr=$(nm "$objfile" 2>/dev/null | awk '$3 == "'$name'" && ($2 == "t" || $2 == "T") {print $1; exit}')
if [[ $base_addr == "" ]] ; then
# address not found
return
@@ -152,7 +152,7 @@ parse_symbol() {
if [[ "${cache[$module,$address]+isset}" == "isset" ]]; then
local code=${cache[$module,$address]}
else
- local code=$(${CROSS_COMPILE}addr2line -i -e "$objfile" "$address")
+ local code=$(${CROSS_COMPILE}addr2line -i -e "$objfile" "$address" 2>/dev/null)
cache[$module,$address]=$code
fi
--
https://chromeos.dev
Add "auto" to the usage message so that it's a little clearer that you
can pass "auto" as the second argument. When passing "auto" the script
tries to find the base path automatically instead of requiring it be
passed on the commandline. Also use [<variable>] to indicate the
variable argument and that it is optional so that we can differentiate
from the literal "auto" that should be passed.
Cc: Jiri Olsa <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Jessica Yu <[email protected]>
Cc: Evan Green <[email protected]>
Cc: Hsin-Yi Wang <[email protected]>
Cc: Konstantin Khlebnikov <[email protected]>
Cc: Sasha Levin <[email protected]>
Signed-off-by: Stephen Boyd <[email protected]>
---
scripts/decode_stacktrace.sh | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/scripts/decode_stacktrace.sh b/scripts/decode_stacktrace.sh
index 20b5af1ebe5e..5fbad61fe490 100755
--- a/scripts/decode_stacktrace.sh
+++ b/scripts/decode_stacktrace.sh
@@ -5,7 +5,7 @@
usage() {
echo "Usage:"
- echo " $0 -r <release> | <vmlinux> [base path] [modules path]"
+ echo " $0 -r <release> | <vmlinux> [<base path>|auto] [<modules path>]"
}
if [[ $1 == "-r" ]] ; then
--
https://chromeos.dev
These arguments are never modified so they can be marked const to
indicate as such.
Cc: Jiri Olsa <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Jessica Yu <[email protected]>
Cc: Evan Green <[email protected]>
Cc: Hsin-Yi Wang <[email protected]>
Signed-off-by: Stephen Boyd <[email protected]>
---
lib/buildid.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/lib/buildid.c b/lib/buildid.c
index 6f1e2903740b..8fe24d6c0925 100644
--- a/lib/buildid.c
+++ b/lib/buildid.c
@@ -48,10 +48,10 @@ static int parse_build_id_buf(unsigned char *build_id,
return -EINVAL;
}
-static inline int parse_build_id(void *page_addr,
+static inline int parse_build_id(const void *page_addr,
unsigned char *build_id,
__u32 *size,
- void *note_start,
+ const void *note_start,
Elf32_Word note_size)
{
/* check for overflow */
@@ -66,7 +66,7 @@ static inline int parse_build_id(void *page_addr,
}
/* Parse build ID from 32-bit ELF */
-static int get_build_id_32(void *page_addr, unsigned char *build_id,
+static int get_build_id_32(const void *page_addr, unsigned char *build_id,
__u32 *size)
{
Elf32_Ehdr *ehdr = (Elf32_Ehdr *)page_addr;
@@ -91,7 +91,7 @@ static int get_build_id_32(void *page_addr, unsigned char *build_id,
}
/* Parse build ID from 64-bit ELF */
-static int get_build_id_64(void *page_addr, unsigned char *build_id,
+static int get_build_id_64(const void *page_addr, unsigned char *build_id,
__u32 *size)
{
Elf64_Ehdr *ehdr = (Elf64_Ehdr *)page_addr;
--
https://chromeos.dev
Kernel doc should use "Return:" instead of "Returns" to properly reflect
the return values.
Cc: Jiri Olsa <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Jessica Yu <[email protected]>
Cc: Evan Green <[email protected]>
Cc: Hsin-Yi Wang <[email protected]>
Signed-off-by: Stephen Boyd <[email protected]>
---
lib/buildid.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/buildid.c b/lib/buildid.c
index 8fe24d6c0925..180a1a9b3b76 100644
--- a/lib/buildid.c
+++ b/lib/buildid.c
@@ -121,7 +121,7 @@ static int get_build_id_64(const void *page_addr, unsigned char *build_id,
* @build_id: buffer to store build id, at least BUILD_ID_SIZE long
* @size: returns actual build id size in case of success
*
- * Returns 0 on success, otherwise error (< 0).
+ * Return: 0 on success, -EINVAL otherwise
*/
int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id,
__u32 *size)
--
https://chromeos.dev
We can use the vmlinux_build_id array here now instead of open coding
it. This mostly consolidates code.
Cc: Jiri Olsa <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Jessica Yu <[email protected]>
Cc: Evan Green <[email protected]>
Cc: Hsin-Yi Wang <[email protected]>
Cc: Dave Young <[email protected]>
Cc: Baoquan He <[email protected]>
Cc: Vivek Goyal <[email protected]>
Cc: <[email protected]>
Signed-off-by: Stephen Boyd <[email protected]>
---
include/linux/buildid.h | 2 +-
include/linux/crash_core.h | 12 ++++-----
kernel/crash_core.c | 50 ++------------------------------------
lib/buildid.c | 2 +-
4 files changed, 10 insertions(+), 56 deletions(-)
diff --git a/include/linux/buildid.h b/include/linux/buildid.h
index 3e8d77a93ec4..3b7a0ff4642f 100644
--- a/include/linux/buildid.h
+++ b/include/linux/buildid.h
@@ -10,7 +10,7 @@ int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id,
__u32 *size);
int build_id_parse_buf(const void *buf, unsigned char *build_id, u32 buf_size);
-#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
+#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID) || IS_ENABLED(CONFIG_CRASH_CORE)
extern unsigned char vmlinux_build_id[BUILD_ID_SIZE_MAX];
void init_vmlinux_build_id(void);
#else
diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
index 206bde8308b2..de62a722431e 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -38,8 +38,12 @@ phys_addr_t paddr_vmcoreinfo_note(void);
#define VMCOREINFO_OSRELEASE(value) \
vmcoreinfo_append_str("OSRELEASE=%s\n", value)
-#define VMCOREINFO_BUILD_ID(value) \
- vmcoreinfo_append_str("BUILD-ID=%s\n", value)
+#define VMCOREINFO_BUILD_ID() \
+ ({ \
+ static_assert(sizeof(vmlinux_build_id) == 20); \
+ vmcoreinfo_append_str("BUILD-ID=%20phN\n", vmlinux_build_id); \
+ })
+
#define VMCOREINFO_PAGESIZE(value) \
vmcoreinfo_append_str("PAGESIZE=%ld\n", value)
#define VMCOREINFO_SYMBOL(name) \
@@ -69,10 +73,6 @@ extern unsigned char *vmcoreinfo_data;
extern size_t vmcoreinfo_size;
extern u32 *vmcoreinfo_note;
-/* raw contents of kernel .notes section */
-extern const void __start_notes __weak;
-extern const void __stop_notes __weak;
-
Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
void *data, size_t data_len);
void final_note(Elf_Word *buf);
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 825284baaf46..29cc15398ee4 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -4,6 +4,7 @@
* Copyright (C) 2002-2004 Eric Biederman <[email protected]>
*/
+#include <linux/buildid.h>
#include <linux/crash_core.h>
#include <linux/utsname.h>
#include <linux/vmalloc.h>
@@ -378,53 +379,6 @@ phys_addr_t __weak paddr_vmcoreinfo_note(void)
}
EXPORT_SYMBOL(paddr_vmcoreinfo_note);
-#define NOTES_SIZE (&__stop_notes - &__start_notes)
-#define BUILD_ID_MAX SHA1_DIGEST_SIZE
-#define NT_GNU_BUILD_ID 3
-
-struct elf_note_section {
- struct elf_note n_hdr;
- u8 n_data[];
-};
-
-/*
- * Add build ID from .notes section as generated by the GNU ld(1)
- * or LLVM lld(1) --build-id option.
- */
-static void add_build_id_vmcoreinfo(void)
-{
- char build_id[BUILD_ID_MAX * 2 + 1];
- int n_remain = NOTES_SIZE;
-
- while (n_remain >= sizeof(struct elf_note)) {
- const struct elf_note_section *note_sec =
- &__start_notes + NOTES_SIZE - n_remain;
- const u32 n_namesz = note_sec->n_hdr.n_namesz;
-
- if (note_sec->n_hdr.n_type == NT_GNU_BUILD_ID &&
- n_namesz != 0 &&
- !strcmp((char *)¬e_sec->n_data[0], "GNU")) {
- if (note_sec->n_hdr.n_descsz <= BUILD_ID_MAX) {
- const u32 n_descsz = note_sec->n_hdr.n_descsz;
- const u8 *s = ¬e_sec->n_data[n_namesz];
-
- s = PTR_ALIGN(s, 4);
- bin2hex(build_id, s, n_descsz);
- build_id[2 * n_descsz] = '\0';
- VMCOREINFO_BUILD_ID(build_id);
- return;
- }
- pr_warn("Build ID is too large to include in vmcoreinfo: %u > %u\n",
- note_sec->n_hdr.n_descsz,
- BUILD_ID_MAX);
- return;
- }
- n_remain -= sizeof(struct elf_note) +
- ALIGN(note_sec->n_hdr.n_namesz, 4) +
- ALIGN(note_sec->n_hdr.n_descsz, 4);
- }
-}
-
static int __init crash_save_vmcoreinfo_init(void)
{
vmcoreinfo_data = (unsigned char *)get_zeroed_page(GFP_KERNEL);
@@ -443,7 +397,7 @@ static int __init crash_save_vmcoreinfo_init(void)
}
VMCOREINFO_OSRELEASE(init_uts_ns.name.release);
- add_build_id_vmcoreinfo();
+ VMCOREINFO_BUILD_ID();
VMCOREINFO_PAGESIZE(PAGE_SIZE);
VMCOREINFO_SYMBOL(init_uts_ns);
diff --git a/lib/buildid.c b/lib/buildid.c
index 180a1a9b3b76..dfc62625cae4 100644
--- a/lib/buildid.c
+++ b/lib/buildid.c
@@ -174,7 +174,7 @@ int build_id_parse_buf(const void *buf, unsigned char *build_id, u32 buf_size)
return parse_build_id_buf(build_id, NULL, buf, buf_size);
}
-#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
+#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID) || IS_ENABLED(CONFIG_CRASH_CORE)
unsigned char vmlinux_build_id[BUILD_ID_SIZE_MAX] __ro_after_init;
/**
--
https://chromeos.dev
Let's use the new printk formats to print the stacktrace entries when
printing a backtrace to the kernel logs. This will include any module's
build ID[1] in it so that offline/crash debugging can easily locate the
debuginfo for a module via something like debuginfod[2].
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Jessica Yu <[email protected]>
Cc: Evan Green <[email protected]>
Cc: Hsin-Yi Wang <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Andy Shevchenko <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Link: https://fedoraproject.org/wiki/Releases/FeatureBuildId [1]
Link: https://sourceware.org/elfutils/Debuginfod.html [2]
Signed-off-by: Stephen Boyd <[email protected]>
---
arch/x86/kernel/dumpstack.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index 299c20f0a38b..ea4fe192189d 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -69,7 +69,7 @@ static void printk_stack_address(unsigned long address, int reliable,
const char *log_lvl)
{
touch_nmi_watchdog();
- printk("%s %s%pB\n", log_lvl, reliable ? "" : "? ", (void *)address);
+ printk("%s %s%pBb\n", log_lvl, reliable ? "" : "? ", (void *)address);
}
static int copy_code(struct pt_regs *regs, u8 *buf, unsigned long src,
--
https://chromeos.dev
On Mon 2021-05-10 17:38:37, Stephen Boyd wrote:
> Let's make kernel stacktraces easier to identify by including the build
> ID[1] of a module if the stacktrace is printing a symbol from a module.
> --- a/include/linux/module.h
> +++ b/include/linux/module.h
> @@ -11,6 +11,7 @@
>
> #include <linux/list.h>
> #include <linux/stat.h>
> +#include <linux/buildid.h>
> #include <linux/compiler.h>
> #include <linux/cache.h>
> #include <linux/kmod.h>
> @@ -364,6 +365,11 @@ struct module {
> /* Unique handle for this module */
> char name[MODULE_NAME_LEN];
>
> +#ifdef CONFIG_STACKTRACE_BUILD_ID
> + /* Module build ID */
> + unsigned char build_id[BUILD_ID_SIZE_MAX];
> +#endif
> +
> /* Sysfs stuff. */
> struct module_kobject mkobj;
> struct module_attribute *modinfo_attrs;
> @@ -627,7 +633,7 @@ void *dereference_module_function_descriptor(struct module *mod, void *ptr);
> const char *module_address_lookup(unsigned long addr,
> unsigned long *symbolsize,
> unsigned long *offset,
> - char **modname,
> + char **modname, const unsigned char **modbuildid,
Nit: It would have been better to follow the existing style and put only one
parameter per-line.
Please, fix it in the next version if there is any. But no need
to resend it just because of this unless Jessica asks for it.
> char *namebuf);
> int lookup_module_symbol_name(unsigned long addr, char *symname);
> int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name);
> diff --git a/kernel/module.c b/kernel/module.c
> index 30479355ab85..a5eaf5188a83 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -4235,7 +4257,7 @@ void * __weak dereference_module_function_descriptor(struct module *mod,
> const char *module_address_lookup(unsigned long addr,
> unsigned long *size,
> unsigned long *offset,
> - char **modname,
> + char **modname, const unsigned char **modbuildid,
Same here.
> char *namebuf)
> {
> const char *ret = NULL;
Otherwise, it looks good.
Reviewed-by: Petr Mladek <[email protected]>
Best Regards,
Petr
On Mon 2021-05-10 17:38:32, Stephen Boyd wrote:
> This series adds the kernel's build ID[1] to the stacktrace header
> printed in oops messages, warnings, etc. and the build ID for any module
> that appears in the stacktrace after the module name. The goal is to
> make the stacktrace more self-contained and descriptive by including the
> relevant build IDs in the kernel logs when something goes wrong. This
> can be used by post processing tools like script/decode_stacktrace.sh
> and kernel developers to easily locate the debug info associated with a
> kernel crash and line up what line and file things started falling apart
> at.
The entire series looks good to me.
I reviewed carefully only the 5th patch touching printk/kallsyms/module
code. I just scanned over the other patches touching kernel code
and did not notice any obvious problem. I did not check the changes
in decode_stacktrace.sh at all.
I tried to get stacktraces on x86_64 and it worked as expected.
Best Regards,
Petr
From: Stephen Boyd
> Sent: 11 May 2021 01:39
>
> This series adds the kernel's build ID[1] to the stacktrace header
> printed in oops messages, warnings, etc. and the build ID for any module
> that appears in the stacktrace after the module name. The goal is to
> make the stacktrace more self-contained and descriptive by including the
> relevant build IDs in the kernel logs when something goes wrong. This
> can be used by post processing tools like script/decode_stacktrace.sh
> and kernel developers to easily locate the debug info associated with a
> kernel crash and line up what line and file things started falling apart
> at.
>
> To show how this can be used I've included a patch to
> decode_stacktrace.sh that downloads the debuginfo from a debuginfod
> server.
...
> Here's an example lkdtm stacktrace on arm64.
>
> WARNING: CPU: 4 PID: 3255 at drivers/misc/lkdtm/bugs.c:83 lkdtm_WARNING+0x28/0x30 [lkdtm]
> Modules linked in: lkdtm rfcomm algif_hash algif_skcipher af_alg xt_cgroup uinput xt_MASQUERADE
> CPU: 4 PID: 3255 Comm: bash Not tainted 5.11 #3 aa23f7a1231c229de205662d5a9e0d4c580f19a1
> Hardware name: Google Lazor (rev3+) with KB Backlight (DT)
...
> x1 : ffffff93fef15788 x0 : ffffffe3622352e0
> Call trace:
> lkdtm_WARNING+0x28/0x30 [lkdtm ed5019fdf5e53be37cb1ba7899292d7e143b259e]
> direct_entry+0x16c/0x1b4 [lkdtm ed5019fdf5e53be37cb1ba7899292d7e143b259e]
> full_proxy_write+0x74/0xa4
Is there any way to get it to print each module ID only once?
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
On Tue, 11 May 2021 12:36:06 +0000
David Laight <[email protected]> wrote:
> > x1 : ffffff93fef15788 x0 : ffffffe3622352e0
> > Call trace:
> > lkdtm_WARNING+0x28/0x30 [lkdtm ed5019fdf5e53be37cb1ba7899292d7e143b259e]
> > direct_entry+0x16c/0x1b4 [lkdtm ed5019fdf5e53be37cb1ba7899292d7e143b259e]
> > full_proxy_write+0x74/0xa4
>
> Is there any way to get it to print each module ID only once?
If there's a trivial way to do that, then perhaps it should be done, but for
now, this patch series isn't as obnoxious as the previous versions. It only
affects stack traces, and I'm fine with that.
-- Steve
From: Steven Rostedt
> Sent: 11 May 2021 13:53
>
> On Tue, 11 May 2021 12:36:06 +0000
> David Laight <[email protected]> wrote:
>
> > > x1 : ffffff93fef15788 x0 : ffffffe3622352e0
> > > Call trace:
> > > lkdtm_WARNING+0x28/0x30 [lkdtm ed5019fdf5e53be37cb1ba7899292d7e143b259e]
> > > direct_entry+0x16c/0x1b4 [lkdtm ed5019fdf5e53be37cb1ba7899292d7e143b259e]
> > > full_proxy_write+0x74/0xa4
> >
> > Is there any way to get it to print each module ID only once?
>
> If there's a trivial way to do that, then perhaps it should be done, but for
> now, this patch series isn't as obnoxious as the previous versions. It only
> affects stack traces, and I'm fine with that.
True. Printing the id in the module list was horrid.
The real downside is all the extra text that will overflow the
in-kernel buffer.
At least it shouldn't be extra lines causing screen wrap.
Unless the variable names are long - hi rust :-)
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
On Tue 2021-05-11 12:58:47, David Laight wrote:
> From: Steven Rostedt
> > Sent: 11 May 2021 13:53
> >
> > On Tue, 11 May 2021 12:36:06 +0000
> > David Laight <[email protected]> wrote:
> >
> > > > x1 : ffffff93fef15788 x0 : ffffffe3622352e0
> > > > Call trace:
> > > > lkdtm_WARNING+0x28/0x30 [lkdtm ed5019fdf5e53be37cb1ba7899292d7e143b259e]
> > > > direct_entry+0x16c/0x1b4 [lkdtm ed5019fdf5e53be37cb1ba7899292d7e143b259e]
> > > > full_proxy_write+0x74/0xa4
> > >
> > > Is there any way to get it to print each module ID only once?
> >
> > If there's a trivial way to do that, then perhaps it should be done, but for
> > now, this patch series isn't as obnoxious as the previous versions. It only
> > affects stack traces, and I'm fine with that.
>
> True. Printing the id in the module list was horrid.
>
> The real downside is all the extra text that will overflow the
> in-kernel buffer.
> At least it shouldn't be extra lines causing screen wrap.
> Unless the variable names are long - hi rust :-)
Note that the ID is printed only when CONFIG_STACKTRACE_BUILD_ID
is enabled. It will be used only by some distros/vendors that
use it to download the debuginfo packages.
Best Regards,
Petr
From: Petr Mladek
> Sent: 11 May 2021 15:22
>
> On Tue 2021-05-11 12:58:47, David Laight wrote:
> > From: Steven Rostedt
> > > Sent: 11 May 2021 13:53
> > >
> > > On Tue, 11 May 2021 12:36:06 +0000
> > > David Laight <[email protected]> wrote:
> > >
> > > > > x1 : ffffff93fef15788 x0 : ffffffe3622352e0
> > > > > Call trace:
> > > > > lkdtm_WARNING+0x28/0x30 [lkdtm ed5019fdf5e53be37cb1ba7899292d7e143b259e]
> > > > > direct_entry+0x16c/0x1b4 [lkdtm ed5019fdf5e53be37cb1ba7899292d7e143b259e]
> > > > > full_proxy_write+0x74/0xa4
> > > >
> > > > Is there any way to get it to print each module ID only once?
> > >
> > > If there's a trivial way to do that, then perhaps it should be done, but for
> > > now, this patch series isn't as obnoxious as the previous versions. It only
> > > affects stack traces, and I'm fine with that.
> >
> > True. Printing the id in the module list was horrid.
> >
> > The real downside is all the extra text that will overflow the
> > in-kernel buffer.
> > At least it shouldn't be extra lines causing screen wrap.
> > Unless the variable names are long - hi rust :-)
>
> Note that the ID is printed only when CONFIG_STACKTRACE_BUILD_ID
> is enabled. It will be used only by some distros/vendors that
> use it to download the debuginfo packages.
Until Ubuntu decide to turn it on :-)
Actually, for the use case, the id could be trimmed significantly.
It is only trying to differentiate between builds of a specific module.
So even 8 digits would be plenty.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
On Tue, May 11, 2021 at 02:31:38PM +0000, David Laight wrote:
> Actually, for the use case, the id could be trimmed significantly.
> It is only trying to differentiate between builds of a specific module.
> So even 8 digits would be plenty.
asked and answered. please review the bidding.
Quoting Petr Mladek (2021-05-11 04:35:21)
> On Mon 2021-05-10 17:38:37, Stephen Boyd wrote:
> > Let's make kernel stacktraces easier to identify by including the build
> > ID[1] of a module if the stacktrace is printing a symbol from a module.
>
> > --- a/include/linux/module.h
> > +++ b/include/linux/module.h
> > @@ -11,6 +11,7 @@
> >
> > #include <linux/list.h>
> > #include <linux/stat.h>
> > +#include <linux/buildid.h>
> > #include <linux/compiler.h>
> > #include <linux/cache.h>
> > #include <linux/kmod.h>
> > @@ -364,6 +365,11 @@ struct module {
> > /* Unique handle for this module */
> > char name[MODULE_NAME_LEN];
> >
> > +#ifdef CONFIG_STACKTRACE_BUILD_ID
> > + /* Module build ID */
> > + unsigned char build_id[BUILD_ID_SIZE_MAX];
> > +#endif
> > +
> > /* Sysfs stuff. */
> > struct module_kobject mkobj;
> > struct module_attribute *modinfo_attrs;
> > @@ -627,7 +633,7 @@ void *dereference_module_function_descriptor(struct module *mod, void *ptr);
> > const char *module_address_lookup(unsigned long addr,
> > unsigned long *symbolsize,
> > unsigned long *offset,
> > - char **modname,
> > + char **modname, const unsigned char **modbuildid,
>
> Nit: It would have been better to follow the existing style and put only one
> parameter per-line.
>
> Please, fix it in the next version if there is any. But no need
> to resend it just because of this unless Jessica asks for it.
Thanks. akpm already picked this series up and fixed this problem.