path: root/kernel
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authorAndrey Ryabinin <a.ryabinin@samsung.com>2015-04-16 12:48:10 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-04-17 09:04:08 -0400
commit9d796e66230205cd3366f5660387bd9ecca9d336 (patch)
tree579863a7da34c7588874c44e951d8309089dad94 /kernel
parent230633d109e35b0a24277498e773edeb79b4a331 (diff)
gcov: fix softlockups
gcov profiling if enabled with other heavy compile-time instrumentation like KASan could trigger following softlockups: NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [swapper/0:1] Modules linked in: irq event stamp: 22823276 hardirqs last enabled at (22823275): [<ffffffff86e8d10d>] mutex_lock_nested+0x7d9/0x930 hardirqs last disabled at (22823276): [<ffffffff86e9521d>] apic_timer_interrupt+0x6d/0x80 softirqs last enabled at (22823172): [<ffffffff811ed969>] __do_softirq+0x4db/0x729 softirqs last disabled at (22823167): [<ffffffff811edfcf>] irq_exit+0x7d/0x15b CPU: 0 PID: 1 Comm: swapper/0 Tainted: G W 3.19.0-05245-gbb33326-dirty #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel- 04/01/2014 task: ffff88006cba8000 ti: ffff88006cbb0000 task.ti: ffff88006cbb0000 RIP: kasan_mem_to_shadow+0x1e/0x1f Call Trace: strcmp+0x28/0x70 get_node_by_name+0x66/0x99 gcov_event+0x4f/0x69e gcov_enable_events+0x54/0x7b gcov_fs_init+0xf8/0x134 do_one_initcall+0x1b2/0x288 kernel_init_freeable+0x467/0x580 kernel_init+0x15/0x18b ret_from_fork+0x7c/0xb0 Kernel panic - not syncing: softlockup: hung tasks Fix this by sticking cond_resched() in gcov_enable_events(). Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> Reported-by: Fengguang Wu <fengguang.wu@intel.com> Cc: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/gcov/base.c b/kernel/gcov/base.c
index b358a802fd18..a744098e4eb7 100644
--- a/kernel/gcov/base.c
+++ b/kernel/gcov/base.c
@@ -18,6 +18,7 @@
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
+#include <linux/sched.h>
#include "gcov.h"
static int gcov_events_enabled;
@@ -107,8 +108,10 @@ void gcov_enable_events(void)
gcov_events_enabled = 1;
/* Perform event callback for previously registered entries. */
- while ((info = gcov_info_next(info)))
+ while ((info = gcov_info_next(info))) {
gcov_event(GCOV_ADD, info);
+ cond_resched();
+ }

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