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authorAlexey Dobriyan <adobriyan@sw.ru>2007-05-08 00:26:46 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-08 11:15:04 -0700
commit19c5d45a09312ca20cd1f9df3fd1a87fe0cb8aac (patch)
treede228e847ea4846e77cd64b35ca74eb5daa3d242
parent72c1bbf308c75a136803d2d76d0e18258be14c7a (diff)
/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 <adobriyan@sw.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/proc/base.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 0697fd089de..ab1b439923e 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);
}