The patch titled Subject: um: properly check all process' threads for a live mm has been added to the -mm tree. Its filename is um-properly-check-all-process-threads-for-a-live-mm.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 *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Anton Vorontsov <anton.vorontsov@xxxxxxxxxx> Subject: um: properly check all process' threads for a live mm kill_off_processes() might miss a valid process, this is because checking for process->mm is not enough. Process' main thread may exit or detach its mm via use_mm(), but other threads may still have a valid mm. To catch this we use find_lock_task_mm(), which walks up all threads and returns an appropriate task (with task lock held). Suggested-by: Oleg Nesterov <oleg@xxxxxxxxxx> Signed-off-by: Anton Vorontsov <anton.vorontsov@xxxxxxxxxx> Cc: Richard Weinberger <richard@xxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/um/kernel/reboot.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff -puN arch/um/kernel/reboot.c~um-properly-check-all-process-threads-for-a-live-mm arch/um/kernel/reboot.c --- a/arch/um/kernel/reboot.c~um-properly-check-all-process-threads-for-a-live-mm +++ a/arch/um/kernel/reboot.c @@ -6,6 +6,7 @@ #include "linux/sched.h" #include "linux/spinlock.h" #include "linux/slab.h" +#include "linux/oom.h" #include "kern_util.h" #include "os.h" #include "skas.h" @@ -25,13 +26,13 @@ static void kill_off_processes(void) read_lock(&tasklist_lock); for_each_process(p) { - task_lock(p); - if (!p->mm) { - task_unlock(p); + struct task_struct *t; + + t = find_lock_task_mm(p); + if (!t) continue; - } - pid = p->mm->context.id.u.pid; - task_unlock(p); + pid = t->mm->context.id.u.pid; + task_unlock(t); os_kill_ptraced_process(pid, 1); } read_unlock(&tasklist_lock); _ Subject: Subject: um: properly check all process' threads for a live mm Patches currently in -mm which might be from anton.vorontsov@xxxxxxxxxx are cpu-introduce-clear_tasks_mm_cpumask-helper.patch arm-use-clear_tasks_mm_cpumask.patch powerpc-use-clear_tasks_mm_cpumask.patch sh-use-clear_tasks_mm_cpumask.patch blackfin-a-couple-of-task-mm-handling-fixes.patch blackfin-fix-possible-deadlock-in-decode_address.patch um-should-hold-tasklist_lock-while-traversing-processes.patch um-fix-possible-race-on-task-mm.patch um-properly-check-all-process-threads-for-a-live-mm.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