The patch titled
oProfile: oops when profile_pc() returns ~0LU
has been added to the -mm tree. Its filename is
oprofile-oops-when-profile_pc-return-0lu.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: oProfile: oops when profile_pc() returns ~0LU
From: Philippe Elie <phil.el@xxxxxxxxxx>
Instruction pointer returned by profile_pc() can be a random value. This
break the assumption than we can safely set struct op_sample.eip field to a
magic value to signal to the per-cpu buffer reader side special event like
task switch ending up in a segfault in get_task_mm() when profile_pc()
return ~0UL. Fixed by sanitizing the sampled eip and reject/log invalid
eip.
Problem reported by Sami Farin, patch tested by him.
Signed-off-by: Philippe Elie <phil.el@xxxxxxxxxx>
Tested-by: Sami Farin <safari-kernel@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/oprofile/cpu_buffer.c | 7 +++++++
drivers/oprofile/cpu_buffer.h | 1 +
drivers/oprofile/oprofile_stats.c | 4 ++++
3 files changed, 12 insertions(+)
diff -puN drivers/oprofile/cpu_buffer.c~oprofile-oops-when-profile_pc-return-0lu drivers/oprofile/cpu_buffer.c
--- a/drivers/oprofile/cpu_buffer.c~oprofile-oops-when-profile_pc-return-0lu
+++ a/drivers/oprofile/cpu_buffer.c
@@ -64,6 +64,8 @@ int alloc_cpu_buffers(void)
b->head_pos = 0;
b->sample_received = 0;
b->sample_lost_overflow = 0;
+ b->backtrace_aborted = 0;
+ b->sample_invalid_eip = 0;
b->cpu = i;
INIT_DELAYED_WORK(&b->work, wq_sync_buffer);
}
@@ -175,6 +177,11 @@ static int log_sample(struct oprofile_cp
cpu_buf->sample_received++;
+ if (pc == ESCAPE_CODE) {
+ cpu_buf->sample_invalid_eip++;
+ return 0;
+ }
+
if (nr_available_slots(cpu_buf) < 3) {
cpu_buf->sample_lost_overflow++;
return 0;
diff -puN drivers/oprofile/cpu_buffer.h~oprofile-oops-when-profile_pc-return-0lu drivers/oprofile/cpu_buffer.h
--- a/drivers/oprofile/cpu_buffer.h~oprofile-oops-when-profile_pc-return-0lu
+++ a/drivers/oprofile/cpu_buffer.h
@@ -42,6 +42,7 @@ struct oprofile_cpu_buffer {
unsigned long sample_received;
unsigned long sample_lost_overflow;
unsigned long backtrace_aborted;
+ unsigned long sample_invalid_eip;
int cpu;
struct delayed_work work;
} ____cacheline_aligned;
diff -puN drivers/oprofile/oprofile_stats.c~oprofile-oops-when-profile_pc-return-0lu drivers/oprofile/oprofile_stats.c
--- a/drivers/oprofile/oprofile_stats.c~oprofile-oops-when-profile_pc-return-0lu
+++ a/drivers/oprofile/oprofile_stats.c
@@ -26,6 +26,8 @@ void oprofile_reset_stats(void)
cpu_buf = &cpu_buffer[i];
cpu_buf->sample_received = 0;
cpu_buf->sample_lost_overflow = 0;
+ cpu_buf->backtrace_aborted = 0;
+ cpu_buf->sample_invalid_eip = 0;
}
atomic_set(&oprofile_stats.sample_lost_no_mm, 0);
@@ -61,6 +63,8 @@ void oprofile_create_stats_files(struct
&cpu_buf->sample_lost_overflow);
oprofilefs_create_ro_ulong(sb, cpudir, "backtrace_aborted",
&cpu_buf->backtrace_aborted);
+ oprofilefs_create_ro_ulong(sb, cpudir, "sample_invalid_eip",
+ &cpu_buf->sample_invalid_eip);
}
oprofilefs_create_ro_atomic(sb, dir, "sample_lost_no_mm",
_
Patches currently in -mm which might be from phil.el@xxxxxxxxxx are
oprofile-oops-when-profile_pc-return-0lu.patch
oprofile-fix-oops-on-x86-32-bit.patch
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