From mboxrd@z Thu Jan 1 00:00:00 1970 From: anton.vorontsov@linaro.org (Anton Vorontsov) Date: Mon, 23 Apr 2012 00:09:25 -0700 Subject: [PATCH 7/9] um: Should hold tasklist_lock while traversing processes In-Reply-To: <20120423070641.GA27702@lizard> References: <20120423070641.GA27702@lizard> Message-ID: <20120423070925.GG30752@lizard> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 --- arch/um/kernel/reboot.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/um/kernel/reboot.c b/arch/um/kernel/reboot.c index 4d93dff..66d754c 100644 --- a/arch/um/kernel/reboot.c +++ b/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); } } -- 1.7.9.2