dump_stack() is used for many different cases, which may require a log
level consistent with other kernel messages surrounding the dump_stack()
call.
Without that, certain systems that are configured to ignore the default
level messages will miss stack traces in critical error reports.
This patch introduces dump_stack_lvl() that behaves similarly to
dump_stack(), but accepts a custom log level.
The old dump_stack() becomes equal to dump_stack_lvl(KERN_DEFAULT).
A somewhat similar patch has been proposed in 2012:
https://lore.kernel.org/lkml/1332493269.2359.9.camel@hebo/
, but wasn't merged.
Cc: Andrew Morton <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: he, bo <[email protected]>
Cc: Yanmin Zhang <[email protected]>
Cc: Prasad Sodagudi <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: [email protected]
Signed-off-by: Alexander Potapenko <[email protected]>
---
v2:
-- export dump_stack_lvl() (spotted by Marco Elver)
---
include/linux/printk.h | 1 +
lib/dump_stack.c | 20 +++++++++++++-------
2 files changed, 14 insertions(+), 7 deletions(-)
diff --git a/include/linux/printk.h b/include/linux/printk.h
index fe7eb2351610..abe274305d79 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -206,6 +206,7 @@ void __init setup_log_buf(int early);
__printf(1, 2) void dump_stack_set_arch_desc(const char *fmt, ...);
void dump_stack_print_info(const char *log_lvl);
void show_regs_print_info(const char *log_lvl);
+extern asmlinkage void dump_stack_lvl(const char *log_lvl) __cold;
extern asmlinkage void dump_stack(void) __cold;
extern void printk_safe_flush(void);
extern void printk_safe_flush_on_panic(void);
diff --git a/lib/dump_stack.c b/lib/dump_stack.c
index f5a33b6f773f..586e3f2c6a15 100644
--- a/lib/dump_stack.c
+++ b/lib/dump_stack.c
@@ -73,10 +73,10 @@ void show_regs_print_info(const char *log_lvl)
dump_stack_print_info(log_lvl);
}
-static void __dump_stack(void)
+static void __dump_stack(const char *log_lvl)
{
- dump_stack_print_info(KERN_DEFAULT);
- show_stack(NULL, NULL, KERN_DEFAULT);
+ dump_stack_print_info(log_lvl);
+ show_stack(NULL, NULL, log_lvl);
}
/**
@@ -87,7 +87,7 @@ static void __dump_stack(void)
#ifdef CONFIG_SMP
static atomic_t dump_lock = ATOMIC_INIT(-1);
-asmlinkage __visible void dump_stack(void)
+asmlinkage __visible void dump_stack_lvl(const char *log_lvl)
{
unsigned long flags;
int was_locked;
@@ -117,7 +117,7 @@ asmlinkage __visible void dump_stack(void)
goto retry;
}
- __dump_stack();
+ __dump_stack(log_lvl);
if (!was_locked)
atomic_set(&dump_lock, -1);
@@ -125,9 +125,15 @@ asmlinkage __visible void dump_stack(void)
local_irq_restore(flags);
}
#else
-asmlinkage __visible void dump_stack(void)
+asmlinkage __visible void dump_stack_lvl(const char *log_lvl)
{
- __dump_stack();
+ __dump_stack(log_lvl);
}
#endif
+EXPORT_SYMBOL(dump_stack_lvl);
+
+asmlinkage __visible void dump_stack(void)
+{
+ dump_stack_lvl(KERN_DEFAULT);
+}
EXPORT_SYMBOL(dump_stack);
--
2.31.1.527.g47e6f16901-goog
Most of the contents of KASAN reports are printed with pr_err(), so use
a consistent logging level to print the memory access stacks.
Cc: Andrew Morton <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Prasad Sodagudi <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: [email protected]
Signed-off-by: Alexander Potapenko <[email protected]>
---
mm/kasan/report.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 14bd51ea2348..8fff1825b22c 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -230,7 +230,7 @@ static void print_address_description(void *addr, u8 tag)
{
struct page *page = kasan_addr_to_page(addr);
- dump_stack();
+ dump_stack_lvl(KERN_ERR);
pr_err("\n");
if (page && PageSlab(page)) {
@@ -375,7 +375,7 @@ void kasan_report_async(void)
pr_err("BUG: KASAN: invalid-access\n");
pr_err("Asynchronous mode enabled: no access details available\n");
pr_err("\n");
- dump_stack();
+ dump_stack_lvl(KERN_ERR);
end_report(&flags, 0);
}
#endif /* CONFIG_KASAN_HW_TAGS */
@@ -420,7 +420,7 @@ static void __kasan_report(unsigned long addr, size_t size, bool is_write,
pr_err("\n");
print_memory_metadata(info.first_bad_addr);
} else {
- dump_stack();
+ dump_stack_lvl(KERN_ERR);
}
end_report(&flags, addr);
--
2.31.1.527.g47e6f16901-goog
On Thu, 6 May 2021 at 12:54, Alexander Potapenko <[email protected]> wrote:
>
> dump_stack() is used for many different cases, which may require a log
> level consistent with other kernel messages surrounding the dump_stack()
> call.
> Without that, certain systems that are configured to ignore the default
> level messages will miss stack traces in critical error reports.
>
> This patch introduces dump_stack_lvl() that behaves similarly to
> dump_stack(), but accepts a custom log level.
> The old dump_stack() becomes equal to dump_stack_lvl(KERN_DEFAULT).
>
> A somewhat similar patch has been proposed in 2012:
> https://lore.kernel.org/lkml/1332493269.2359.9.camel@hebo/
> , but wasn't merged.
>
> Cc: Andrew Morton <[email protected]>
> Cc: Petr Mladek <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: he, bo <[email protected]>
> Cc: Yanmin Zhang <[email protected]>
> Cc: Prasad Sodagudi <[email protected]>
> Cc: Dmitry Vyukov <[email protected]>
> Cc: Marco Elver <[email protected]>
> Cc: [email protected]
> Signed-off-by: Alexander Potapenko <[email protected]>
Reviewed-by: Marco Elver <[email protected]>
> ---
>
> v2:
> -- export dump_stack_lvl() (spotted by Marco Elver)
> ---
> include/linux/printk.h | 1 +
> lib/dump_stack.c | 20 +++++++++++++-------
> 2 files changed, 14 insertions(+), 7 deletions(-)
>
> diff --git a/include/linux/printk.h b/include/linux/printk.h
> index fe7eb2351610..abe274305d79 100644
> --- a/include/linux/printk.h
> +++ b/include/linux/printk.h
> @@ -206,6 +206,7 @@ void __init setup_log_buf(int early);
> __printf(1, 2) void dump_stack_set_arch_desc(const char *fmt, ...);
> void dump_stack_print_info(const char *log_lvl);
> void show_regs_print_info(const char *log_lvl);
> +extern asmlinkage void dump_stack_lvl(const char *log_lvl) __cold;
> extern asmlinkage void dump_stack(void) __cold;
> extern void printk_safe_flush(void);
> extern void printk_safe_flush_on_panic(void);
> diff --git a/lib/dump_stack.c b/lib/dump_stack.c
> index f5a33b6f773f..586e3f2c6a15 100644
> --- a/lib/dump_stack.c
> +++ b/lib/dump_stack.c
> @@ -73,10 +73,10 @@ void show_regs_print_info(const char *log_lvl)
> dump_stack_print_info(log_lvl);
> }
>
> -static void __dump_stack(void)
> +static void __dump_stack(const char *log_lvl)
> {
> - dump_stack_print_info(KERN_DEFAULT);
> - show_stack(NULL, NULL, KERN_DEFAULT);
> + dump_stack_print_info(log_lvl);
> + show_stack(NULL, NULL, log_lvl);
> }
>
> /**
> @@ -87,7 +87,7 @@ static void __dump_stack(void)
> #ifdef CONFIG_SMP
> static atomic_t dump_lock = ATOMIC_INIT(-1);
>
> -asmlinkage __visible void dump_stack(void)
> +asmlinkage __visible void dump_stack_lvl(const char *log_lvl)
> {
> unsigned long flags;
> int was_locked;
> @@ -117,7 +117,7 @@ asmlinkage __visible void dump_stack(void)
> goto retry;
> }
>
> - __dump_stack();
> + __dump_stack(log_lvl);
>
> if (!was_locked)
> atomic_set(&dump_lock, -1);
> @@ -125,9 +125,15 @@ asmlinkage __visible void dump_stack(void)
> local_irq_restore(flags);
> }
> #else
> -asmlinkage __visible void dump_stack(void)
> +asmlinkage __visible void dump_stack_lvl(const char *log_lvl)
> {
> - __dump_stack();
> + __dump_stack(log_lvl);
> }
> #endif
> +EXPORT_SYMBOL(dump_stack_lvl);
> +
> +asmlinkage __visible void dump_stack(void)
> +{
> + dump_stack_lvl(KERN_DEFAULT);
> +}
> EXPORT_SYMBOL(dump_stack);
> --
> 2.31.1.527.g47e6f16901-goog
>
On Thu, 6 May 2021 at 12:54, Alexander Potapenko <[email protected]> wrote:
>
> Most of the contents of KASAN reports are printed with pr_err(), so use
> a consistent logging level to print the memory access stacks.
>
> Cc: Andrew Morton <[email protected]>
> Cc: Andrey Ryabinin <[email protected]>
> Cc: Prasad Sodagudi <[email protected]>
> Cc: Dmitry Vyukov <[email protected]>
> Cc: Marco Elver <[email protected]>
> Cc: [email protected]
> Signed-off-by: Alexander Potapenko <[email protected]>
Reviewed-by: Marco Elver <[email protected]>
> ---
> mm/kasan/report.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/mm/kasan/report.c b/mm/kasan/report.c
> index 14bd51ea2348..8fff1825b22c 100644
> --- a/mm/kasan/report.c
> +++ b/mm/kasan/report.c
> @@ -230,7 +230,7 @@ static void print_address_description(void *addr, u8 tag)
> {
> struct page *page = kasan_addr_to_page(addr);
>
> - dump_stack();
> + dump_stack_lvl(KERN_ERR);
> pr_err("\n");
>
> if (page && PageSlab(page)) {
> @@ -375,7 +375,7 @@ void kasan_report_async(void)
> pr_err("BUG: KASAN: invalid-access\n");
> pr_err("Asynchronous mode enabled: no access details available\n");
> pr_err("\n");
> - dump_stack();
> + dump_stack_lvl(KERN_ERR);
> end_report(&flags, 0);
> }
> #endif /* CONFIG_KASAN_HW_TAGS */
> @@ -420,7 +420,7 @@ static void __kasan_report(unsigned long addr, size_t size, bool is_write,
> pr_err("\n");
> print_memory_metadata(info.first_bad_addr);
> } else {
> - dump_stack();
> + dump_stack_lvl(KERN_ERR);
> }
>
> end_report(&flags, addr);
> --
> 2.31.1.527.g47e6f16901-goog
>
On Thu, 6 May 2021 12:54:04 +0200 Alexander Potapenko <[email protected]> wrote:
> dump_stack() is used for many different cases, which may require a log
> level consistent with other kernel messages surrounding the dump_stack()
> call.
> Without that, certain systems that are configured to ignore the default
> level messages will miss stack traces in critical error reports.
>
> This patch introduces dump_stack_lvl() that behaves similarly to
> dump_stack(), but accepts a custom log level.
> The old dump_stack() becomes equal to dump_stack_lvl(KERN_DEFAULT).
>
> A somewhat similar patch has been proposed in 2012:
> https://lore.kernel.org/lkml/1332493269.2359.9.camel@hebo/
> , but wasn't merged.
Um yeah, I dropped the ball on that one, didn't I? I suspect pretty
much all dump_stack() callsites should be using this.