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author | Mikulas Patocka <mpatocka@redhat.com> | 2022-08-09 14:32:13 -0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-08-09 15:03:02 -0700 |
commit | d4252071b97d2027d246f6a82cbee4d52f618b47 (patch) | |
tree | 9e84cfc4657863176f75029d50a1969f54918e05 /certs | |
parent | e394ff83bbca1c72427b1feb5c6b9d4dad832f01 (diff) |
add barriers to buffer_uptodate and set_buffer_uptodate
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: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'certs')
0 files changed, 0 insertions, 0 deletions