Messages in this thread Patch in this message | | | Date | Thu, 15 Mar 2007 12:09:25 +0300 | From | Alexey Dobriyan <> | Subject | [PATCH] /proc/*/oom_score oops re badness |
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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[1] 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.
[1] 2.6.21-rc3-something + patches for all proc races I've already posted + patch for proxying proc directories similar to proxying proc regular files.
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru> ---
fs/proc/base.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -310,7 +310,9 @@ static int proc_oom_score(struct task_st 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); } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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