The patch titled call_usermodehelper: simplify/fix UMH_NO_WAIT case has been added to the -mm tree. Its filename is call_usermodehelper-simplify-fix-umh_no_wait-case.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: call_usermodehelper: simplify/fix UMH_NO_WAIT case From: Oleg Nesterov <oleg@xxxxxxxxxx> __call_usermodehelper(UMH_NO_WAIT) has 2 problems: - if kernel_thread() fails, call_usermodehelper_freeinfo() is not called. - for unknown reason UMH_NO_WAIT has UMH_WAIT_PROC logic, we spawn yet another thread which waits until the user mode application exits. Change the UMH_NO_WAIT code to use ____call_usermodehelper() instead of wait_for_helper(), and do call_usermodehelper_freeinfo() unconditionally. We can rely on CLONE_VFORK, do_fork(CLONE_VFORK) until the child exits or execs. With or without this patch UMH_NO_WAIT does not report the error if kernel_thread() fails, this is correct since the caller doesn't wait for result. Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/kmod.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff -puN kernel/kmod.c~call_usermodehelper-simplify-fix-umh_no_wait-case kernel/kmod.c --- a/kernel/kmod.c~call_usermodehelper-simplify-fix-umh_no_wait-case +++ a/kernel/kmod.c @@ -205,10 +205,7 @@ static int wait_for_helper(void *data) sub_info->retval = ret; } - if (sub_info->wait == UMH_NO_WAIT) - call_usermodehelper_freeinfo(sub_info); - else - complete(sub_info->complete); + complete(sub_info->complete); return 0; } @@ -217,13 +214,13 @@ static void __call_usermodehelper(struct { struct subprocess_info *sub_info = container_of(work, struct subprocess_info, work); - pid_t pid; enum umh_wait wait = sub_info->wait; + pid_t pid; /* CLONE_VFORK: wait until the usermode helper has execve'd * successfully We need the data structures to stay around * until that is done. */ - if (wait == UMH_WAIT_PROC || wait == UMH_NO_WAIT) + if (wait == UMH_WAIT_PROC) pid = kernel_thread(wait_for_helper, sub_info, CLONE_FS | CLONE_FILES | SIGCHLD); else @@ -232,6 +229,7 @@ static void __call_usermodehelper(struct switch (wait) { case UMH_NO_WAIT: + call_usermodehelper_freeinfo(sub_info); break; case UMH_WAIT_PROC: _ Patches currently in -mm which might be from oleg@xxxxxxxxxx are origin.patch linux-next.patch posix-cpu-timers-reset-expire-cache-when-no-timer-is-running.patch cpu-timers-simplify-rlimit_cpu-handling.patch cpu-timers-cleanup-arm_timer.patch cpu-timers-return-correct-previous-timer-reload-value.patch cpu-timers-change-sigev_none-timer-implementation.patch cpu-timers-assure-to-not-iterate-over-all-threads-in-fastpath_timer_check.patch cpu-timers-optimize-run_posix_cpu_timers.patch proc-cleanup-remove-unused-assignments.patch kmod-add-init-function-to-usermodehelper.patch exec-replace-call_usermodehelper_pipe-with-use-of-umh-init-function-and-resolve-limit.patch umh-creds-convert-call_usermodehelper_keys-to-use-subprocess_info-init.patch umh-creds-kill-subprocess_info-cred-logic.patch call_usermodehelper-no-need-to-unblock-signals.patch wait_for_helper-sigchld-from-user-space-can-lead-to-use-after-free.patch call_usermodehelper-simplify-fix-umh_no_wait-case.patch call_usermodehelper-umh_wait_exec-ignores-kernel_thread-failure.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html