[26.04_linux-nvidia] NVIDIA: SAUCE: ovl: keep err zero after successful ovl_cache_get()#425
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BugLink: https://bugs.launchpad.net/bugs/2150640 ovl_iterate_merged() stores PTR_ERR(cache) in err before checking IS_ERR(cache). On success err holds the truncated cache pointer and can be returned as a bogus non-zero error. The syzbot reproducer reaches this through overlay-on-overlay readdir: getdents64 iterate_dir(outer overlay file) ovl_iterate_merged() ovl_cache_get() ovl_dir_read_merged() ovl_dir_read() iterate_dir(inner overlay file) ovl_iterate_merged() Only compute PTR_ERR(cache) on the error path. Fixes: d25e4b7 ("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> Acked-by: Jamie Nguyen <jamien@nvidia.com> Acked-by: Matthew R. Ochs <mochs@nvidia.com> Acked-by: Carol L Soto <csoto@nvidia.com> (backported from https://lore.kernel.org/r/20260514144258.3068715-1-nirmoyd@nvidia.com)
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PR Validation ReportPatchscan ✅ No Missing FixesAll cherry-picked commits checked — no missing upstream fixes found. PR Lint ❌ Errors foundDetailsChecking 1 commits...
Cherry-pick digest:
E: f3e134440913 ("NVIDIA: SAUCE: ovl: keep err zero after "): backport trailer order: MISSING: backporter SOB after (backported from)
┌──────────────┬──────────────────────────────────────────────────────────────────┬────────────┬─────────┬───────────────────────────┐
│ Local │ Referenced upstream / Patch subject │ Patch-ID │ Subject │ SoB chain │
├──────────────┼──────────────────────────────────────────────────────────────────┼────────────┼─────────┼───────────────────────────┤
│ f3e134440913 │ ovl: keep err zero after successful ovl_cache_get() │ match │ found │ MISSING: backporter SOB a │
└──────────────┴──────────────────────────────────────────────────────────────────┴────────────┴─────────┴───────────────────────────┘
Lint: all checks passed.
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Boro reviewLatest watcher review: open review Head: This comment is maintained by nv-pr-bot. It is updated when the GitHub watcher publishes a newer review. |
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Summary
Fix NVBug 6144764 on
26.04_linux-nvidiaby keepingerrzero after a successfulovl_cache_get()inovl_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 toPTR_ERR(), truncating pointer bits into a bogusintthat can later be returned as a non-errno value.Sibling BOS PR: #423
Bug Links
Validation
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.OVL_SYZ_DONE rc=0and no Oops/KASAN/panic markers.