Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=19c5d45a09312ca20cd1f9df3fd1a87fe0cb8aac
Commit: 19c5d45a09312ca20cd1f9df3fd1a87fe0cb8aac
Parent: 72c1bbf308c75a136803d2d76d0e18258be14c7a
Author: Alexey Dobriyan <[EMAIL PROTECTED]>
AuthorDate: Tue May 8 00:26:46 2007 -0700
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Tue May 8 11:15:04 2007 -0700
/proc/*/oom_score oops re badness
Eternal quest to make
while true; do cat /proc/fs/xfs/stat >/dev/null 2>/dev/null; done
while true; do find /proc -type f 2>/dev/null | xargs cat >/dev/null
2>/dev/null; done
while true; do modprobe xfs; rmmod xfs; done
work reliably continues and now kernel oopses in the following way:
BUG: unable to handle ... at virtual address 6b6b6b6b
EIP is at badness
process: cat
proc_oom_score
proc_info_read
sys_fstat64
vfs_read
proc_info_read
sys_read
Failing code is prefetch hidden in list_for_each_entry() in badness().
badness() is reachable from two points. One is proc_oom_score, another
is out_of_memory() => select_bad_process() => badness().
Second path grabs tasklist_lock, while first doesn't.
Signed-off-by: Alexey Dobriyan <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
fs/proc/base.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 0697fd0..ab1b439 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -314,7 +314,9 @@ static int proc_oom_score(struct task_struct *task, char
*buffer)
struct timespec uptime;
do_posix_clock_monotonic_gettime(&uptime);
+ read_lock(&tasklist_lock);
points = badness(task, uptime.tv_sec);
+ read_unlock(&tasklist_lock);
return sprintf(buffer, "%lu\n", points);
}
-
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