diff options
| author | Manfred Spraul <manfred@colorfullife.com> | 2004-12-02 15:47:45 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2004-12-02 15:47:45 -0800 |
| commit | 01eb4811efe377ac2311329186e61f2392dee75c (patch) | |
| tree | 1f761749ea731aeb917ee25669ca2d7c90613b57 /include/linux | |
| parent | dfecb2536027830170e587712c5a4b1ccfbd544e (diff) | |
[PATCH] proc_pid_status() oops fix
proc_pid_status dereferences pointers in the task structure even if the
task is already dead. This is probably the reason for the oops described
in
http://bugme.osdl.org/show_bug.cgi?id=3812
The attached patch removes the pointer dereferences by using pid_alive()
for testing that the task structure contents is still valid before
dereferencing them. The task structure itself is guaranteed to be valid -
we hold a reference count.
Signed-Off-By: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/sched.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 0c8262c6d6b8..440393fcd5c7 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -671,6 +671,19 @@ static inline pid_t process_group(struct task_struct *tsk) return tsk->signal->pgrp; } +/** + * pid_alive - check that a task structure is not stale + * @p: Task structure to be checked. + * + * Test if a process is not yet dead (at most zombie state) + * If pid_alive fails, then pointers within the task structure + * can be stale and must not be dereferenced. + */ +static inline int pid_alive(struct task_struct *p) +{ + return p->pids[PIDTYPE_PID].nr != 0; +} + extern void free_task(struct task_struct *tsk); extern void __put_task_struct(struct task_struct *tsk); #define get_task_struct(tsk) do { atomic_inc(&(tsk)->usage); } while(0) |