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author | Sagi Grimberg <sagi@grimberg.me> | 2021-06-16 14:19:36 -0700 |
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committer | Christoph Hellwig <hch@lst.de> | 2021-08-16 14:42:22 +0200 |
commit | e7006de6c23803799be000a5dcce4d916a36541a (patch) | |
tree | c8ae69e3cca3580db8680b7a9558ae07325d7860 /drivers/watchdog | |
parent | 3b01a9d0caa8276d9ce314e09610f7fb70f49a00 (diff) | |
download | linux-stable-e7006de6c23803799be000a5dcce4d916a36541a.tar.gz linux-stable-e7006de6c23803799be000a5dcce4d916a36541a.tar.bz2 linux-stable-e7006de6c23803799be000a5dcce4d916a36541a.zip |
nvme: code command_id with a genctr for use-after-free validation
We cannot detect a (perhaps buggy) controller that is sending us
a completion for a request that was already completed (for example
sending a completion twice), this phenomenon was seen in the wild
a few times.
So to protect against this, we use the upper 4 msbits of the nvme sqe
command_id to use as a 4-bit generation counter and verify it matches
the existing request generation that is incrementing on every execution.
The 16-bit command_id structure now is constructed by:
| xxxx | xxxxxxxxxxxx |
gen request tag
This means that we are giving up some possible queue depth as 12 bits
allow for a maximum queue depth of 4095 instead of 65536, however we
never create such long queues anyways so no real harm done.
Suggested-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Acked-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Tested-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'drivers/watchdog')
0 files changed, 0 insertions, 0 deletions