On ia64 and ppc64, the function pointer does not point the
entry address of the function, but the address of function
discriptor (which contains the entry address and misc
data.) Since the kprobes passes the function pointer stored
by NOKPROBE_SYMBOL() to kallsyms_lookup_size_offset() for
initalizing its blacklist, it fails and reports many errors
as below.
Failed to find blacklist 0001013168300000
Failed to find blacklist 0001013000f0a000
Failed to find blacklist 000101315f70a000
Failed to find blacklist 000101324c80a000
Failed to find blacklist 0001013063f0a000
Failed to find blacklist 000101327800a000
Failed to find blacklist 0001013277f0a000
Failed to find blacklist 000101315a70a000
Failed to find blacklist 0001013277e0a000
Failed to find blacklist 000101305a20a000
Failed to find blacklist 0001013277d0a000
Failed to find blacklist 00010130bdc0a000
Failed to find blacklist 00010130dc20a000
Failed to find blacklist 000101309a00a000
Failed to find blacklist 0001013277c0a000
Failed to find blacklist 0001013277b0a000
Failed to find blacklist 0001013277a0a000
Failed to find blacklist 000101327790a000
Failed to find blacklist 000101303140a000
Failed to find blacklist 0001013a3280a000
To fix this bug, this uses arch_deref_entry_point() to get
the function entry address for kallsyms_lookup_size_offset()
instead of the raw function pointer.
Suzuki also pointed out that blacklist entries should also
be updated by that too.
Changes in v6:
- Update patch description.
- Remove "#include <linux/types.h>" which is no more needed
because we don't use new function_entry() macro any more.
Changes in v5:
- Use arch_deref_entry_point() instead of function_entry().
Changes in v4:
- Add kernel_text_address() check for verifying the address.
- Moved on the latest linus tree.
Changes in v3:
- Fix a bug to get blacklist address based on function entry
instead of function descriptor. (Suzuki's work, Thanks!)
Changes in V2:
- Use function_entry() macro when lookin up symbols instead
of storing it.
- Update for the latest -next.
Signed-off-by: Masami Hiramatsu <[email protected]>
Fixed-by: Suzuki K. Poulose <[email protected]>
Reported-by: Tony Luck <[email protected]>
Tested-by: Tony Luck <[email protected]>
Tested-by: Michael Ellerman <[email protected]>
Acked-by: Michael Ellerman <[email protected]> (for powerpc)
Acked-by: Benjamin Herrenschmidt <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Ananth N Mavinakayanahalli <[email protected]>
Cc: Kevin Hao <[email protected]>
Cc: [email protected]
Cc: [email protected]
---
kernel/kprobes.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 3214289..734e9a7 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2037,19 +2037,23 @@ static int __init populate_kprobe_blacklist(unsigned long *start,
{
unsigned long *iter;
struct kprobe_blacklist_entry *ent;
- unsigned long offset = 0, size = 0;
+ unsigned long entry, offset = 0, size = 0;
for (iter = start; iter < end; iter++) {
- if (!kallsyms_lookup_size_offset(*iter, &size, &offset)) {
- pr_err("Failed to find blacklist %p\n", (void *)*iter);
+ entry = arch_deref_entry_point((void *)*iter);
+
+ if (!kernel_text_address(entry) ||
+ !kallsyms_lookup_size_offset(entry, &size, &offset)) {
+ pr_err("Failed to find blacklist at %p\n",
+ (void *)entry);
continue;
}
ent = kmalloc(sizeof(*ent), GFP_KERNEL);
if (!ent)
return -ENOMEM;
- ent->start_addr = *iter;
- ent->end_addr = *iter + size;
+ ent->start_addr = entry;
+ ent->end_addr = entry + size;
INIT_LIST_HEAD(&ent->list);
list_add_tail(&ent->list, &kprobe_blacklist);
}
Commit-ID: d81b4253b0f0f1e7b7e03b0cd0f80cab18bc4d7b
Gitweb: http://git.kernel.org/tip/d81b4253b0f0f1e7b7e03b0cd0f80cab18bc4d7b
Author: Masami Hiramatsu <[email protected]>
AuthorDate: Thu, 17 Jul 2014 11:44:11 +0000
Committer: Ingo Molnar <[email protected]>
CommitDate: Fri, 18 Jul 2014 06:23:40 +0200
kprobes: Fix "Failed to find blacklist" probing errors on ia64 and ppc64
On ia64 and ppc64, function pointers do not point to the
entry address of the function, but to the address of a
function descriptor (which contains the entry address and misc
data).
Since the kprobes code passes the function pointer stored
by NOKPROBE_SYMBOL() to kallsyms_lookup_size_offset() for
initalizing its blacklist, it fails and reports many errors,
such as:
Failed to find blacklist 0001013168300000
Failed to find blacklist 0001013000f0a000
[...]
To fix this bug, use arch_deref_entry_point() to get the
function entry address for kallsyms_lookup_size_offset()
instead of the raw function pointer.
Suzuki also pointed out that blacklist entries should also
be updated as well.
Reported-by: Tony Luck <[email protected]>
Fixed-by: Suzuki K. Poulose <[email protected]>
Tested-by: Tony Luck <[email protected]>
Tested-by: Michael Ellerman <[email protected]>
Signed-off-by: Masami Hiramatsu <[email protected]>
Acked-by: Michael Ellerman <[email protected]> (for powerpc)
Acked-by: Benjamin Herrenschmidt <[email protected]>
Cc: Jeremy Fitzhardinge <[email protected]>
Cc: [email protected]
Cc: Paul Mackerras <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Fenghua Yu <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Rusty Russell <[email protected]>
Cc: Chris Wright <[email protected]>
Cc: [email protected]
Cc: Kevin Hao <[email protected]>
Cc: Ananth N Mavinakayanahalli <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Linus Torvalds <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
kernel/kprobes.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 3214289..734e9a7 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2037,19 +2037,23 @@ static int __init populate_kprobe_blacklist(unsigned long *start,
{
unsigned long *iter;
struct kprobe_blacklist_entry *ent;
- unsigned long offset = 0, size = 0;
+ unsigned long entry, offset = 0, size = 0;
for (iter = start; iter < end; iter++) {
- if (!kallsyms_lookup_size_offset(*iter, &size, &offset)) {
- pr_err("Failed to find blacklist %p\n", (void *)*iter);
+ entry = arch_deref_entry_point((void *)*iter);
+
+ if (!kernel_text_address(entry) ||
+ !kallsyms_lookup_size_offset(entry, &size, &offset)) {
+ pr_err("Failed to find blacklist at %p\n",
+ (void *)entry);
continue;
}
ent = kmalloc(sizeof(*ent), GFP_KERNEL);
if (!ent)
return -ENOMEM;
- ent->start_addr = *iter;
- ent->end_addr = *iter + size;
+ ent->start_addr = entry;
+ ent->end_addr = entry + size;
INIT_LIST_HEAD(&ent->list);
list_add_tail(&ent->list, &kprobe_blacklist);
}