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b=Ug0XbjGTbmYUSr9coKi7L+zPsvUJtshCsGuhrTUbK0kDKJr5wFYjESkyUuuLYTS2P ppWztHXaekhoIiqW3BDOsW2uzs/UgX7PgFwcsNdLFt8BCtd3av0eoqH3wK6srN9Do3 DqvVkmYWTKhPoH3hz8bf51TDCHgQsYZt47xzR+6kMTUqyFVMPltg4+OJJ2mJDhD4hj 3ZnGCgAwVm5yDgn5wPzK6XMmRYonihfaBlkmihoSh6ndh8FlTMTOQXRP7wK8QKBucN w5thdoufb9NwOS6FLktCivMwokg/pT2Evsub2UfTu7AXlGh2a3C5EY3ziuDIOijRE7 qVf1IbWe8OzvA== From: Christian Brauner Date: Mon, 21 Sep 2026 15:45:02 +0200 Subject: [PATCH v3 13/17] fork: move the coredump and exec checks into create_io_thread() MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260921-work-coredump-fixes-v3-13-8e4adb1619e6@kernel.org> References: <20260921-work-coredump-fixes-v3-0-8e4adb1619e6@kernel.org> In-Reply-To: <20260921-work-coredump-fixes-v3-0-8e4adb1619e6@kernel.org> To: Oleg Nesterov , Chris Mason , linux-fsdevel@vger.kernel.org Cc: Jens Axboe , Alexander Viro , Jan Kara , NeilBrown , Ingo Molnar , Peter Zijlstra , linux-mm@kvack.org, io-uring@vger.kernel.org, "Christian Brauner (Amutable)" X-Mailer: b4 0.17-dev-db0b7 X-Developer-Signature: v=1; a=openpgp-sha256; l=1335; i=brauner@kernel.org; h=from:subject:message-id; bh=B63fTvBDfUtF/BGISUIaLDChkQm0aNRJ/uKFQUOzDOo=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWRtNLkzQX9O3u1LrD/S6zk+Rj6/njbrRoG2yU8jlRUn5 22JXyNk11HKwiDGxSArpsji0G4SLrecp2KzUaYGzBxWJpAhDFycAjARke+MDPcT2F/Lqy/ySJZ9 6nI+9fXRz/5GbZu4c1lelE5Zm9H4ZR7DP1tBIbYQQYYd6+Smrf++MeuQ6mVhC1+z1HW6EcfWmh5 9wAQA X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: EC18EC0005 X-Stat-Signature: apn9qzqeej46tbtw6jegs43dja1smc9z X-HE-Tag: 1789998353-257879 X-HE-Meta: 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 qV1I4jTm 0CmG25KVrwr/m9Giva1thcYmgvlkO2u7KCstbDL1Q5KAy/m7CCRJcs9TcA9P5AHW5Lb0SnbUuDrJi8SyVhsk1CA4h2QbVxtEL6l4+RBAMppRp8/fyj7eg6nvUp5EsZBcMxle7A3hk6lOR01sf86Amqtup1rwA5CRk5Pnei5xmZa7OYy045pUqC8jYlu9al7pJQmRZlZTludM2toEa4L1M99m/baDFg5uq6nFe6HhyvGT6dyK+ibyalyYmWp24XA4Ano0yln0pPwwWx0fCMswH+hBe9/fuKJDRCOWxCB1V18bsk9rOS1HSN3kjtYHFM81Qhast Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Only a PF_USER_WORKER thread returns from get_signal() after a fatal signal and can go on to create a thread. get_signal() sets PF_SIGNALED before it dumps core and before it lets a PF_USER_WORKER thread return. That flags sticks. The exec'ing thread itself is never signaled. But it doesn't need the check anyway as we moved cancellation of io_uring requests before de_thread(). create_io_thread() is the only way a signaled thread creates another one. vhost_task_create() is reached from ioctls alone. io_should_retry_thread() doesn't retry -EINTR, so io-wq callers give up the same way they did when copy_process() refused. Suggested-by: Oleg Nesterov Link: https://lore.kernel.org/r/aq0VLTyxNatFmLOK@redhat.com Signed-off-by: Christian Brauner (Amutable) --- kernel/fork.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/fork.c b/kernel/fork.c index 50f5b3e2ca87..ede9f02bef47 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2706,6 +2706,10 @@ struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node) .user_worker = 1, }; + /* A creator past its fatal signal gets no thread. */ + if (current->flags & PF_SIGNALED) + return ERR_PTR(-EINTR); + return copy_process(NULL, 0, node, &args); } -- 2.53.0