linuxkpi: Fix an off-by-one error in the kfifo implementation
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Authored by markj on Mon, Apr 13, 3:05 AM.

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emaste
bz

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linuxkpi

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rG52d2fc702b85: linuxkpi: Fix an off-by-one error in the kfifo implementation

Summary

"total" is the number of slots in the array, so wraparound needs to be
done when "first" or "last" is greater than or equal to the number of
slots.

Reported by: Stanislav Fort <stanislav.fort@aisle.com>

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rG FreeBSD src repository

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Tests Not Applicable

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markj created this revision.Mon, Apr 13, 3:05 AM

Herald added subscribers: emaste, imp. · View Herald TranscriptMon, Apr 13, 3:05 AM

Harbormaster completed remote builds in B72169: Diff 175405.Mon, Apr 13, 3:05 AM

markj requested review of this revision.Mon, Apr 13, 3:05 AM

emaste accepted this revision.Mon, Apr 13, 1:50 PM

This revision is now accepted and ready to land.Mon, Apr 13, 1:50 PM

This seems to be correct given we do the check after updating the values.

Do we know what is using the kfifo these days; I am just curious where the report came from?
I know I wrote it for ath10k (which is not connected to the official build yet) and it was only stubs before.
Hmm drm-kmod 6.10 amdgpu uses it for RAS poison events. OK.

In D56371#1290515, @bz wrote:

This seems to be correct given we do the check after updating the values.

Do we know what is using the kfifo these days; I am just curious where the report came from?

I believe it comes from analyzing kernel sources rather than testing any affected drivers.

I know I wrote it for ath10k (which is not connected to the official build yet) and it was only stubs before.
Hmm drm-kmod 6.10 amdgpu uses it for RAS poison events. OK.

Seems to be used by mt76 too.

In D56371#1290640, @markj wrote:

In D56371#1290515, @bz wrote:

This seems to be correct given we do the check after updating the values.

Do we know what is using the kfifo these days; I am just curious where the report came from?

I believe it comes from analyzing kernel sources rather than testing any affected drivers.

Ah, makes sense :)

I know I wrote it for ath10k (which is not connected to the official build yet) and it was only stubs before.
Hmm drm-kmod 6.10 amdgpu uses it for RAS poison events. OK.

Seems to be used by mt76 too.

For (old) mt7610/12/30 cards. Not even sure if my stash goes so far back. Not compiled on FreeBSD. I do have a 7615 which is worthwhile as on SoCs as well but doesn't use the mt76x02 "lib" parts.

Closed by commit rG52d2fc702b85: linuxkpi: Fix an off-by-one error in the kfifo implementation (authored by markj). · Explain WhyWed, Apr 15, 1:47 PM

This revision was automatically updated to reflect the committed changes.

markj added a commit: rG52d2fc702b85: linuxkpi: Fix an off-by-one error in the kfifo implementation.