tree b41bec77e5e5123f8f5349eb01ced9ee8fd9a924 parent 187a27845a9dc1c3da3995e24625ccf2e7a346aa author NeilBrown <[EMAIL PROTECTED]> Sun, 17 Apr 2005 05:26:41 -0700 committer Linus Torvalds <[EMAIL PROTECTED]> Sun, 17 Apr 2005 05:26:41 -0700
[PATCH] md: close a small race in md thread deregistration There is a tiny race when de-registering an MD thread, in that the thread could disappear before it is set a SIGKILL, causing send_sig to have problems. This is most easily closed by holding tasklist_lock between enabling the thread to exit (setting ->run to NULL) and telling it to exit. (akpm: ick. Needs to use kthread API and stop using signals) Signed-off-by: Neil Brown <[EMAIL PROTECTED]> Signed-off-by: Andrew Morton <[EMAIL PROTECTED]> Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]> md/md.c | 20 ++++++++------------ 1 files changed, 8 insertions(+), 12 deletions(-) Index: drivers/md/md.c =================================================================== --- b4374b7af235c0d14bc722999cd1d8d3e2743c0d/drivers/md/md.c (mode:100644 sha1:aa72c88a024f7ef06f4c32263497a379c0bd7094) +++ b41bec77e5e5123f8f5349eb01ced9ee8fd9a924/drivers/md/md.c (mode:100644 sha1:44a164965546c3a57d60c2a9d90d9dce2c4962c7) @@ -2840,16 +2840,6 @@ return thread; } -static void md_interrupt_thread(mdk_thread_t *thread) -{ - if (!thread->tsk) { - MD_BUG(); - return; - } - dprintk("interrupting MD-thread pid %d\n", thread->tsk->pid); - send_sig(SIGKILL, thread->tsk, 1); -} - void md_unregister_thread(mdk_thread_t *thread) { struct completion event; @@ -2857,9 +2847,15 @@ init_completion(&event); thread->event = &event; + + /* As soon as ->run is set to NULL, the task could disappear, + * so we need to hold tasklist_lock until we have sent the signal + */ + dprintk("interrupting MD-thread pid %d\n", thread->tsk->pid); + read_lock(&tasklist_lock); thread->run = NULL; - thread->name = NULL; - md_interrupt_thread(thread); + send_sig(SIGKILL, thread->tsk, 1); + read_unlock(&tasklist_lock); wait_for_completion(&event); kfree(thread); } - To unsubscribe from this list: send the line "unsubscribe bk-commits-head" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html