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8238b45798
There are several places in the kernel where wait_on_bit is not followed by a memory barrier (for example, in drivers/md/dm-bufio.c:new_read). On architectures with weak memory ordering, it may happen that memory accesses that follow wait_on_bit are reordered before wait_on_bit and they may return invalid data. Fix this class of bugs by introducing a new function "test_bit_acquire" that works like test_bit, but has acquire memory ordering semantics. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Acked-by: Will Deacon <will@kernel.org> Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
20 lines
701 B
C
20 lines
701 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
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#define _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
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#include <asm-generic/bitops/generic-non-atomic.h>
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#define arch___set_bit generic___set_bit
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#define arch___clear_bit generic___clear_bit
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#define arch___change_bit generic___change_bit
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#define arch___test_and_set_bit generic___test_and_set_bit
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#define arch___test_and_clear_bit generic___test_and_clear_bit
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#define arch___test_and_change_bit generic___test_and_change_bit
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#define arch_test_bit generic_test_bit
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#define arch_test_bit_acquire generic_test_bit_acquire
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#include <asm-generic/bitops/non-instrumented-non-atomic.h>
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#endif /* _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ */
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