bpf: avoid sleeping in invalid context during sock_map_delete_elem path #6127
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The syzkaller report exposed a BUG: “sleeping function called from
invalid context” in sock_map_delete_elem, which happens when
`bpf_test_timer_enter()` disables preemption but the delete path later
invokes a sleeping function while still in that context. Specifically:
- The crash trace shows `bpf_test_timer_enter()` acquiring a
preempt_disable path (via t->mode == NO_PREEMPT), but the symmetric
release path always calls migrate_enable(), mismatching the earlier
disable.
- As a result, preemption remains disabled across the
sock_map_delete_elem path, leading to a sleeping call under an invalid
context. :contentReference[oaicite:0]{index=0}
To fix this, normalize the disable/enable pairing: always use
migrate_disable()/migrate_enable() regardless of t->mode. This ensures
that we never remain with preemption disabled unintentionally when
entering the delete path, and avoids invalid-context sleeping.
Reported-by: [email protected]
Closes: https://syzkaller.appspot.com/bug?extid=1f1fbecb9413cdbfbef8
Suggested-by: Yonghong Song <[email protected]>
Suggested-by: Menglong Dong <[email protected]>
Co-authored-by: Sahil Chandna <[email protected]>
Signed-off-by: Brahmajit Das <[email protected]>
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At least one diff in series https://patchwork.kernel.org/project/netdevbpf/list/?series=1010865 expired. Closing PR. |
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Pull request for series with
subject: bpf: avoid sleeping in invalid context during sock_map_delete_elem path
version: 2
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=1010865