[26.04_linux-nvidia] NVIDIA: SAUCE: ovl: keep err zero after successful ovl_cache_get()

[nirmoy]

Summary

Fix NVBug 6144764 on 26.04_linux-nvidia by keeping err zero after a successful ovl_cache_get() in ovl_iterate_merged().

The installer crash is an overlayfs readdir failure while rsync reads through overlayfs during BaseOS/DGX OS installation. The bad path is the same as syzbot a16fb0cce329a320661c: a successful cache pointer is passed to PTR_ERR(), truncating pointer bits into a bogus int that can later be returned as a non-errno value.

Sibling BOS PR: #423

Bug Links

• NVBug: https://nvbugspro.nvidia.com/bug/6144764
• Launchpad: https://bugs.launchpad.net/bugs/2150640
• syzbot: https://syzkaller.appspot.com/bug?extid=a16fb0cce329a320661c
• Backported from: https://lore.kernel.org/r/20260514144258.3068715-1-nirmoyd@nvidia.com

Validation

• Cherry-picked cleanly onto upstream/26.04_linux-nvidia.
• git show --check --format=short HEAD: clean.
• scripts/checkpatch.pl --strict --ignore COMMIT_LOG_USE_LINK,COMMIT_LOG_LONG_LINE --git HEAD: 0 errors, 0 warnings.
• Earlier validation on arm64 virtme/KVM KASAN:
  • unpatched / Amir-only controls reproduced the overlayfs crash.
  • patched v2 completed 5/5 runs clean with OVL_SYZ_DONE rc=0 and no Oops/KASAN/panic markers.

[github-actions]

PR Validation Report

PR Lint ✅ All checks passed

Details

Checking 1 commits...

Cherry-pick digest:
┌──────────────┬──────────────────────────────────────────────────────────────────┬────────────┬─────────┬───────────────────────────┐
│ Local        │ Referenced upstream / Patch subject                              │ Patch-ID   │ Subject │ SoB chain                 │
├──────────────┼──────────────────────────────────────────────────────────────────┼────────────┼─────────┼───────────────────────────┤
│ b6d5ce0fbbd5 │ ovl: keep err zero after successful ovl_cache_get()              │ match      │ found   │ ok, backporter: nirmoyd   │
└──────────────┴──────────────────────────────────────────────────────────────────┴────────────┴─────────┴───────────────────────────┘

Lint: all checks passed.

[nirmoy]

Boro review

Latest watcher review: open review

Head: b6d5ce0fbbd5

This comment is maintained by nv-pr-bot. It is updated when the GitHub watcher publishes a newer review.

[nvmochs]

@nirmoy Sounds like this should be in -next tomorrow and make next week's 7.1-rc. Our target build is for Thursday, so should be able to pick from -next tomorrow (assuming it shows up).

[nvmochs]

@nirmoy Can you fix up the trailers in this commit?

[nvmochs]

@nirmoy

All of these should be removed, no?

Acked-by: Jamie Nguyen <jamien@nvidia.com>
Acked-by: Matthew R. Ochs <mochs@nvidia.com>
Acked-by: Carol L Soto <csoto@nvidia.com>

I would think the trailers would look like:

Fixes: https://github.com/NVIDIA/NV-Kernels/commit/d25e4b739f8378419f990983f2542160e79738c5 ("ovl: refactor ovl_iterate() and port to cred guard")
Reported-by: syzbot+a16fb0cce329a320661c@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=a16fb0cce329a320661c
Cc: stable@vger.kernel.org
Signed-off-by: Nirmoy Das <nirmoyd@nvidia.com>
(backported from https://lore.kernel.org/r/20260514144258.3068715-1-nirmoyd@nvidia.com)
Signed-off-by: Nirmoy Das <nirmoyd@nvidia.com>

Then once we review, Brad will add the Acks and his sign-off when applying the patch.

[nvmochs]

Thanks Nirmoy, no further issues from me!

Acked-by: Matthew R. Ochs <mochs@nvidia.com>

[clsotog]

Acked-by: Carol L Soto <csoto@nvidia.com>

[nvmochs]

Merged, closing PR.

7df64053ee60 (nresolute/main-next) NVIDIA: SAUCE: ovl: keep err zero after successful ovl_cache_get()