Commit 372370dc authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Zheng Zengkai
Browse files

add barriers to buffer_uptodate and set_buffer_uptodate

stable inclusion
from stable-v5.10.137
commit 57f2ee517dec126d091fe11f995ecb75ee39b09d
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I60PLB

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=57f2ee517dec126d091fe11f995ecb75ee39b09d



--------------------------------

commit d4252071 upstream.

Let's have a look at this piece of code in __bread_slow:

	get_bh(bh);
	bh->b_end_io = end_buffer_read_sync;
	submit_bh(REQ_OP_READ, 0, bh);
	wait_on_buffer(bh);
	if (buffer_uptodate(bh))
		return bh;

Neither wait_on_buffer nor buffer_uptodate contain any memory barrier.
Consequently, if someone calls sb_bread and then reads the buffer data,
the read of buffer data may be executed before wait_on_buffer(bh) on
architectures with weak memory ordering and it may return invalid data.

Fix this bug by adding a memory barrier to set_buffer_uptodate and an
acquire barrier to buffer_uptodate (in a similar way as
folio_test_uptodate and folio_mark_uptodate).

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Reviewed-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: default avatarWei Li <liwei391@huawei.com>
parent f34c64c0
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