From 0d7cb9e5e45b6483737ad381b12794175dd89288 Mon Sep 17 00:00:00 2001 From: Josh Boyer Date: Apr 19 2013 19:40:19 +0000 Subject: Add patch to fix RCU splat from perf events --- diff --git a/events-protect-access-via-task-subsys-state-check.patch b/events-protect-access-via-task-subsys-state-check.patch new file mode 100644 index 0000000..a7d3972 --- /dev/null +++ b/events-protect-access-via-task-subsys-state-check.patch @@ -0,0 +1,61 @@ +The following RCU splat indicates lack of RCU protection: + +[ 953.267649] =============================== +[ 953.267652] [ INFO: suspicious RCU usage. ] +[ 953.267657] 3.9.0-0.rc6.git2.4.fc19.ppc64p7 #1 Not tainted +[ 953.267661] ------------------------------- +[ 953.267664] include/linux/cgroup.h:534 suspicious rcu_dereference_check() usage! +[ 953.267669] +[ 953.267669] other info that might help us debug this: +[ 953.267669] +[ 953.267675] +[ 953.267675] rcu_scheduler_active = 1, debug_locks = 0 +[ 953.267680] 1 lock held by glxgears/1289: +[ 953.267683] #0: (&sig->cred_guard_mutex){+.+.+.}, at: [] .prepare_bprm_creds+0x34/0xa0 +[ 953.267700] +[ 953.267700] stack backtrace: +[ 953.267704] Call Trace: +[ 953.267709] [c0000001f0d1b6e0] [c000000000016e30] .show_stack+0x130/0x200 (unreliable) +[ 953.267717] [c0000001f0d1b7b0] [c0000000001267f8] .lockdep_rcu_suspicious+0x138/0x180 +[ 953.267724] [c0000001f0d1b840] [c0000000001d43a4] .perf_event_comm+0x4c4/0x690 +[ 953.267731] [c0000001f0d1b950] [c00000000027f6e4] .set_task_comm+0x84/0x1f0 +[ 953.267737] [c0000001f0d1b9f0] [c000000000280414] .setup_new_exec+0x94/0x220 +[ 953.267744] [c0000001f0d1ba70] [c0000000002f665c] .load_elf_binary+0x58c/0x19b0 +[ 953.267751] [c0000001f0d1bbc0] [c00000000027e724] .search_binary_handler+0x254/0x680 +[ 953.267758] [c0000001f0d1bca0] [c0000000002800dc] .do_execve_common.isra.17+0x76c/0x860 +[ 953.267764] [c0000001f0d1bd90] [c000000000280698] .SyS_execve+0x58/0x90 +[ 953.267771] [c0000001f0d1be30] [c000000000009e60] syscall_exit+0x0/0x98 + +This commit therefore adds the required RCU read-side critical section to +perf_event_comm(). + +Reported-by: Adam Jackson +Signed-off-by: Paul E. McKenney +Tested-by: Gustavo Luiz Duarte + +diff --git a/kernel/events/core.c b/kernel/events/core.c +index b0cd865..8db9551 100644 +--- a/kernel/events/core.c ++++ b/kernel/events/core.c +@@ -4593,6 +4593,7 @@ void perf_event_comm(struct task_struct *task) + struct perf_event_context *ctx; + int ctxn; + ++ rcu_read_lock(); + for_each_task_context_nr(ctxn) { + ctx = task->perf_event_ctxp[ctxn]; + if (!ctx) +@@ -4600,6 +4601,7 @@ void perf_event_comm(struct task_struct *task) + + perf_event_enable_on_exec(ctx); + } ++ rcu_read_unlock(); + + if (!atomic_read(&nr_comm_events)) + return; + +-- +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/ diff --git a/kernel.spec b/kernel.spec index 4742bd4..3ae5b81 100644 --- a/kernel.spec +++ b/kernel.spec @@ -757,6 +757,8 @@ Patch25010: wireless-regulatory-fix-channel-disabling-race-condition.patch #rhbz 951241 Patch25011: iwlwifi-fix-freeing-uninitialized-pointer.patch +Patch25012: events-protect-access-via-task-subsys-state-check.patch + # END OF PATCH DEFINITIONS %endif @@ -1463,6 +1465,8 @@ ApplyPatch wireless-regulatory-fix-channel-disabling-race-condition.patch #rhbz 951241 ApplyPatch iwlwifi-fix-freeing-uninitialized-pointer.patch +ApplyPatch events-protect-access-via-task-subsys-state-check.patch + # END OF PATCH APPLICATIONS %endif @@ -2295,6 +2299,9 @@ fi # and build. %changelog +* Fri Apr 19 2013 Josh Boyer +- Add patch to fix RCU splat from perf events + * Fri Apr 19 2013 Peter Robinson - Temporaily disable cpu idle on ARM as it appears to be causing stability issues - Minor ARM config updates