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| author | Oleg Nesterov <oleg@tv-sign.ru> | 2006-10-28 10:38:49 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-10-28 11:30:54 -0700 |
| commit | fca178c0c6e8d52a1875be36b070f30884ebfae9 (patch) | |
| tree | 4bce17647edd3fae6b0ba96407cd1c02037b11d1 /kernel/taskstats.c | |
| parent | 6e6d9fa6f95e382bb2d5725dda18b9e811418e79 (diff) | |
| download | lwn-fca178c0c6e8d52a1875be36b070f30884ebfae9.tar.gz lwn-fca178c0c6e8d52a1875be36b070f30884ebfae9.zip | |
[PATCH] fill_tgid: fix task_struct leak and possible oops
1. fill_tgid() forgets to do put_task_struct(first).
2. release_task(first) can happen after fill_tgid() drops tasklist_lock,
it is unsafe to dereference first->signal.
This is a temporary fix, imho the locking should be reworked.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@sgi.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/taskstats.c')
| -rw-r--r-- | kernel/taskstats.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/kernel/taskstats.c b/kernel/taskstats.c index 5d6a8c54ee85..9aeee511a463 100644 --- a/kernel/taskstats.c +++ b/kernel/taskstats.c @@ -237,14 +237,17 @@ static int fill_tgid(pid_t tgid, struct task_struct *tgidtsk, } else get_task_struct(first); - /* Start with stats from dead tasks */ - spin_lock_irqsave(&first->signal->stats_lock, flags); - if (first->signal->stats) - memcpy(stats, first->signal->stats, sizeof(*stats)); - spin_unlock_irqrestore(&first->signal->stats_lock, flags); tsk = first; read_lock(&tasklist_lock); + /* Start with stats from dead tasks */ + if (first->signal) { + spin_lock_irqsave(&first->signal->stats_lock, flags); + if (first->signal->stats) + memcpy(stats, first->signal->stats, sizeof(*stats)); + spin_unlock_irqrestore(&first->signal->stats_lock, flags); + } + do { if (tsk->exit_state == EXIT_ZOMBIE && thread_group_leader(tsk)) continue; @@ -264,7 +267,7 @@ static int fill_tgid(pid_t tgid, struct task_struct *tgidtsk, * Accounting subsytems can also add calls here to modify * fields of taskstats. */ - + put_task_struct(first); return 0; } |