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Vishnu Razdan 49d565ede4 io_uring/io-wq: fix worker accounting when canceling creation callbacks ... commit 297b5ccea4 upstream. create_worker_cb() reserves an io-wq worker slot only after its task-work callback runs. If the callback is canceled before then, io_worker_cancel_cb() still decrements acct->nr_workers. When an existing worker retires with its creation callback pending, that worker has already decremented the same account's worker count. The resulting undercount permits worker creation beyond the account's configured limit. On an AST2600 OpenBMC system, an unchanged sensor daemon reached 4,291 threads with the original kernel. With an equivalent downstream fix, 25 passive samples under its normal workload showed 6-9 threads. Decrement nr_workers only when the canceled callback is not create_worker_cb(). Continuation callbacks still release their reserved slot, and both callback types retain the existing running-count, reference-count, and create-state cleanup. [ Backport: retain the existing worker->wqe->lock protecting worker accounting. ] Fixes: 1d5f5ea7cb ("io-wq: remove worker to owner tw dependency") Cc: stable@vger.kernel.org Assisted-by: Codex:gpt-5.6-sol Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de> Link: https://patch.msgid.link/20260811-vrazdan-io-wq-b4-submit-v1-1-719ced16c921@openai.com Signed-off-by: Vishnu Razdan <vrazdan@openai.com> Signed-off-by: Sasha Levin <sashal@kernel.org>		History 2026-09-02 14:27:25 +02:00
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io-wq.c	io_uring/io-wq: fix worker accounting when canceling creation callbacks	2026-09-02 14:27:25 +02:00
io-wq.h	io_uring: break out of iowq iopoll on teardown	2023-09-19 12:22:54 +02:00
io_uring.c	io_uring/poll: fix signed comparison in io_poll_get_ownership()	2026-06-19 13:33:39 +02:00
Makefile	io_uring: move to separate directory	2022-12-14 11:37:31 +01:00