ext4: fix potential race between online resizing and write operations

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commit 1d0c3924a9 upstream.

During an online resize an array of pointers to buffer heads gets
replaced so it can get enlarged.  If there is a racing block
allocation or deallocation which uses the old array, and the old array
has gotten reused this can lead to a GPF or some other random kernel
memory getting modified.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=206443
Link: https://lore.kernel.org/r/20200221053458.730016-2-tytso@mit.edu
Reported-by: Suraj Jitindar Singh <surajjs@amazon.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Theodore Ts'o 2020-02-15 16:40:37 -05:00 • committed by Greg Kroah-Hartman

parent ea14796541

commit 9866b5910b

4 changed files with 97 additions and 25 deletions

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14

fs/ext4/balloc.c

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20

fs/ext4/ext4.h

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55

fs/ext4/resize.c

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33

fs/ext4/super.c

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