The patch titled Subject: um: should hold tasklist_lock while traversing processes has been added to the -mm tree. Its filename is um-should-hold-tasklist_lock-while-traversing-processes.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: should hold tasklist_lock while traversing processes Traversing the tasks requires holding tasklist_lock, otherwise it is unsafe. p.s. However, I'm not sure that calling os_kill_ptraced_process() in the atomic context is correct. It seem to work, but please take a closer look. Signed-off-by: Anton Vorontsov <anton.vorontsov@xxxxxxxxxx> Cc: Richard Weinberger <richard@xxxxxx> Cc: Oleg Nesterov <oleg@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/um/kernel/reboot.c | 3 +++ 1 file changed, 3 insertions(+) diff -puN arch/um/kernel/reboot.c~um-should-hold-tasklist_lock-while-traversing-processes arch/um/kernel/reboot.c --- a/arch/um/kernel/reboot.c~um-should-hold-tasklist_lock-while-traversing-processes +++ a/arch/um/kernel/reboot.c @@ -4,6 +4,7 @@ */ #include "linux/sched.h" +#include "linux/spinlock.h" #include "linux/slab.h" #include "kern_util.h" #include "os.h" @@ -22,6 +23,7 @@ static void kill_off_processes(void) struct task_struct *p; int pid; + read_lock(&tasklist_lock); for_each_process(p) { if (p->mm == NULL) continue; @@ -29,6 +31,7 @@ static void kill_off_processes(void) pid = p->mm->context.id.u.pid; os_kill_ptraced_process(pid, 1); } + read_unlock(&tasklist_lock); } } _ Subject: Subject: um: should hold tasklist_lock while traversing processes 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