https://github.com/torvalds/linux
Revision 952041a8639a7a3a73a2b6573cb8aa8518bc39f8 authored by Peter Zijlstra on 18 July 2019, 13:03:15 UTC, committed by Ingo Molnar on 25 July 2019, 13:39:24 UTC
While reviewing rwsem down_slowpath, Will noticed ldsem had a copy of
a bug we just found for rwsem.
X = 0;
CPU0 CPU1
rwsem_down_read()
for (;;) {
set_current_state(TASK_UNINTERRUPTIBLE);
X = 1;
rwsem_up_write();
rwsem_mark_wake()
atomic_long_add(adjustment, &sem->count);
smp_store_release(&waiter->task, NULL);
if (!waiter.task)
break;
...
}
r = X;
Allows 'r == 0'.
Reported-by: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 4898e640caf0 ("tty: Add timed, writer-prioritized rw semaphore")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
1 parent 99143f8
Tip revision: 952041a8639a7a3a73a2b6573cb8aa8518bc39f8 authored by Peter Zijlstra on 18 July 2019, 13:03:15 UTC
tty/ldsem, locking/rwsem: Add missing ACQUIRE to read_failed sleep loop
tty/ldsem, locking/rwsem: Add missing ACQUIRE to read_failed sleep loop
Tip revision: 952041a
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| include | ||
| init | ||
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| kernel | ||
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| .clang-format | -rw-r--r-- | 14.6 KB |
| .cocciconfig | -rw-r--r-- | 59 bytes |
| .get_maintainer.ignore | -rw-r--r-- | 71 bytes |
| .gitattributes | -rw-r--r-- | 30 bytes |
| .gitignore | -rw-r--r-- | 1.6 KB |
| .mailmap | -rw-r--r-- | 12.0 KB |
| COPYING | -rw-r--r-- | 423 bytes |
| CREDITS | -rw-r--r-- | 97.1 KB |
| Kbuild | -rw-r--r-- | 1.5 KB |
| Kconfig | -rw-r--r-- | 595 bytes |
| MAINTAINERS | -rw-r--r-- | 509.8 KB |
| Makefile | -rw-r--r-- | 59.1 KB |
| README | -rw-r--r-- | 727 bytes |
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