Messages in this thread Patch in this message | | | Date | Mon, 15 Nov 2004 20:45:32 +0000 (GMT) | From | Hugh Dickins <> | Subject | [PATCH] -mm check_rlimit oops on p->signal |
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The p->signal check in account_system_time is insufficient. If the timer interrupt hits near the end of exit_notify, after EXIT_ZOMBIE has been set, another cpu may release_task (NULLifying p->signal) in between account_system_time's check and check_rlimit's dereference. Nor should account_it_prof risk send_sig. But surely account_user_time is safe?
Signed-off-by: Hugh Dickins <hugh@veritas.com>
--- 2.6.10-rc1-mm5/kernel/sched.c 2004-11-11 12:40:12.000000000 +0000 +++ linux/kernel/sched.c 2004-11-14 20:41:26.851384984 +0000 @@ -2333,8 +2333,7 @@ void account_user_time(struct task_struc p->utime = cputime_add(p->utime, cputime); /* Check for signals (SIGVTALRM, SIGPROF, SIGXCPU & SIGKILL). */ - if (likely(p->signal)) - check_rlimit(p, cputime); + check_rlimit(p, cputime); account_it_virt(p, cputime); account_it_prof(p, cputime); @@ -2362,9 +2361,10 @@ void account_system_time(struct task_str p->stime = cputime_add(p->stime, cputime); /* Check for signals (SIGPROF, SIGXCPU & SIGKILL). */ - if (likely(p->signal)) + if (likely(p->signal && p->exit_state < EXIT_ZOMBIE)) { check_rlimit(p, cputime); - account_it_prof(p, cputime); + account_it_prof(p, cputime); + } /* Add system time to cpustat. */ tmp = cputime_to_cputime64(cputime); - 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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