4.9-stable review patch. If anyone has any objections, please let me know.
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From: Will Deacon will.deacon@arm.com
[ Upstream commit 3fcbb8260a87efb691d837e8cd24e81f65b3eb70 ]
In 4.19-rc1, Eugeniy reported weird boot and IO errors on ARC HSDK
| INFO: task syslogd:77 blocked for more than 10 seconds. | Not tainted 4.19.0-rc1-00007-gf213acea4e88 #40 | "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this | message. | syslogd D 0 77 76 0x00000000 | | Stack Trace: | __switch_to+0x0/0xac | __schedule+0x1b2/0x730 | io_schedule+0x5c/0xc0 | __lock_page+0x98/0xdc | find_lock_entry+0x38/0x100 | shmem_getpage_gfp.isra.3+0x82/0xbfc | shmem_fault+0x46/0x138 | handle_mm_fault+0x5bc/0x924 | do_page_fault+0x100/0x2b8 | ret_from_exception+0x0/0x8
He bisected to 84c6591103db ("locking/atomics, asm-generic/bitops/lock.h: Rewrite using atomic_fetch_*()")
This commit however only unmasked the real issue introduced by commit 4aef66c8ae9 ("locking/atomic, arch/arc: Fix build") which missed the retry-if-scond-failed branch in atomic_fetch_##op() macros.
The bisected commit started using atomic_fetch_##op() macros for building the rest of atomics.
Fixes: 4aef66c8ae9 ("locking/atomic, arch/arc: Fix build") Reported-by: Eugeniy Paltsev paltsev@synopsys.com Acked-by: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Will Deacon will.deacon@arm.com Signed-off-by: Vineet Gupta vgupta@synopsys.com [vgupta: wrote changelog] Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arc/include/asm/atomic.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/arc/include/asm/atomic.h +++ b/arch/arc/include/asm/atomic.h @@ -84,7 +84,7 @@ static inline int atomic_fetch_##op(int "1: llock %[orig], [%[ctr]] \n" \ " " #asm_op " %[val], %[orig], %[i] \n" \ " scond %[val], [%[ctr]] \n" \ - " \n" \ + " bnz 1b \n" \ : [val] "=&r" (val), \ [orig] "=&r" (orig) \ : [ctr] "r" (&v->counter), \