Messages in this thread | | | Date | Sat, 18 Jan 2014 12:55:51 +0530 | Subject | BUG: spinlock lockup | From | naveen yadav <> |
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Dear All,
We are using 3.8.x kernel on ARM, We are facing soft lockup issue. Following are the logs.
BUG: spinlock lockup suspected on CPU#0, process1/525 lock: 0xd8ac9a64, .magic: dead4ead, .owner: <none>/-1, .owner_cpu: -1
1 . Looks like lock is available as owner is -1, why arch_spin_trylock is getting failed ?
2. There is a patch : ARM: spinlock: retry trylock operation if strex fails on free lock http://permalink.gmane.org/gmane.linux.ports.arm.kernel/240913 In this patch, A loop has been added around strexeq %2, %0, [%3]". {Comment "retry the trylock operation if the lock appears to be free but the strex reported failure"}
but arch_spin_trylock is called by __spin_lock_debug and its already getting called in loops. So what purpose is resolves?
static void __spin_lock_debug(raw_spinlock_t *lock) { u64 i; u64 loops = loops_per_jiffy * HZ;
for (i = 0; i < loops; i++) { if (arch_spin_trylock(&lock->raw_lock)) return; __delay(1); } /* lockup suspected: */ spin_dump(lock, "lockup suspected"); }
3. Is this patch useful to us, How can we reproduce this scenario ? Scenario : Lock is available but arch_spin_trylock is returning as failure
Thanks
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