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author | Al Viro <viro@zeniv.linux.org.uk> | 2016-06-08 04:26:55 +0300 |
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committer | Al Viro <viro@zeniv.linux.org.uk> | 2016-06-08 04:26:55 +0300 |
commit | 3d56c25e3bb0726a5c5e16fc2d9e38f8ed763085 (patch) | |
tree | 3b76a5c52293cc900bd55a839831939a4ac47d44 /fs/namei.c | |
parent | e6ec03a25f12b312b7e0c037fe4a6471c4ee5665 (diff) | |
download | linux-3d56c25e3bb0726a5c5e16fc2d9e38f8ed763085.tar.xz |
fix d_walk()/non-delayed __d_free() race
Ascend-to-parent logics in d_walk() depends on all encountered child
dentries not getting freed without an RCU delay. Unfortunately, in
quite a few cases it is not true, with hard-to-hit oopsable race as
the result.
Fortunately, the fix is simiple; right now the rule is "if it ever
been hashed, freeing must be delayed" and changing it to "if it
ever had a parent, freeing must be delayed" closes that hole and
covers all cases the old rule used to cover. Moreover, pipes and
sockets remain _not_ covered, so we do not introduce RCU delay in
the cases which are the reason for having that delay conditional
in the first place.
Cc: stable@vger.kernel.org # v3.2+ (and watch out for __d_materialise_dentry())
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/namei.c')
0 files changed, 0 insertions, 0 deletions