From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out162-62-57-137.mail.qq.com (out162-62-57-137.mail.qq.com [162.62.57.137]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 90472469D for ; Mon, 16 Mar 2026 00:57:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=162.62.57.137 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773622666; cv=none; b=BRnFku9MqFlXDbfGSoh3mCpzrgaakPReTaz0W/zxbX8B7MJfISRqODXtFIPpYP3yKHvWH78HWGPpfHEQinRe+hQmPMnrdEQDK/CHSexqbyqReStWpcTZ2tDc/r/LLp8XxqWpIruDj7QqLcIPmsv5CP9cumFlr0QjgO/FpTk9GwE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773622666; c=relaxed/simple; bh=mLo8MvWFWTGmfWv+JOFWzhkTvpDAh4mky2DdHtcqIhY=; h=Message-ID:From:To:Cc:Subject:Date:In-Reply-To:References: MIME-Version; b=Ft450lkH3/dtz3h9Y9214ijA0ZHo9RzosCgfzCUsQZdLo/knot7L9nNux9WnFk4mqFD5FzX/5XvJ/hpmIiwotIJGymtET6NKpCtxpvGfqRo5IinFUtlJGzYNlOy3sAv0iIUa4JsRy7SQofRBkX0DK5Kxc9MvmP6ddPX/bGux+8Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=qq.com; spf=pass smtp.mailfrom=qq.com; dkim=pass (1024-bit key) header.d=qq.com header.i=@qq.com header.b=esSaARV+; arc=none smtp.client-ip=162.62.57.137 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=qq.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=qq.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=qq.com header.i=@qq.com header.b="esSaARV+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=qq.com; s=s201512; t=1773622653; bh=Bp/zM+3Y7wKDDNo2FBdtKF2iTqolYyL/GSp2HIdg5X4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=esSaARV+b7sAGoX1saXJWBSM7KdLnS2yPsjlZrFYxBh0KGttDCKAudxHYuGXkB6ea o8Zkn4kTSwSoHUl3npWdJtH6VCxUO683lrVOtdJN39AOVwwBkjDaxIjB1il6jZQ8d4 q6Wlg8gaxRsABOrZ8rjEjsmnQsNBBlljAb66811Y= Received: from lxu-ped-host.. ([111.198.231.89]) by newxmesmtplogicsvrszb51-0.qq.com (NewEsmtp) with SMTP id E5E01AC6; Mon, 16 Mar 2026 08:57:30 +0800 X-QQ-mid: xmsmtpt1773622650tk2mxxeo0 Message-ID: X-QQ-XMAILINFO: Nx5J06Esz7r7xbYMHuFPJJRva2ikNx3wpQnpMz510K2XYOIXHzQeU6gHWkV/T4 j7s657gfnP8C4aQlBpTytDyuQemvVjF8WHulrc+xLI9moebvHbn+uBWszQWN6VjS4b7ZQhRecSVU /kItB828CMBZpimglnYQYETGojUMm3y0VD+OZGjVAJtxkPGca285/xNpFlE7hwgRtYPLStpC+ozL KzptsPNYDi8raxu6hT0x/o9/5ZYlihD+piYXFEFI7YsFxLuvqGwAkTLO2GeNqvUFVMBxRmcepbUZ 13alE0A9op9boDCDv+v7rhkFShAT5mrQzMn5HpMUuY+wv35Tvr7kLSP4LTeOdvuKqF2j3Vf55rCA X2Y4gXc4Nu3L+B1ETEeSXoGRxs3OzwOJVevnTrMvM4DT5Z9rr+/db//hWdiKlcil90REpgzAt9y6 dHlgO9xv42F8c5mgurx0AF8KcjXGhtoYuDdKYFelUIRe6lbmMkQCdkrjJayQ0V+7pECxNGJUb5xG H09lCSbvDWKK+XfjmNHMyFRY42fw3BxzgaqlCUuA0Gs7MgOy0hWyclyglSLQ9MVRtZj2oJ4m+usM b/O2OSrfwUi2TqR3pTsIS6Etr20ur72hKVBIlS88dKj70x1HgR4+eZiQw+EvIYrlyaajR6J1VDQG uEGkl2/JJaTDXUgCL92hcPVRVrNECSbi5ZHMMm9EmeNLD9jubSgR5fc445dG0uBPwdZQLQBvM9rX hlAwts0ygg1UO7B2Gc/KpKgSj8TneAvfa1DcIQgChLduQ5KEwVbu/40xVvVBPIiH5jiRpOisdyf8 XmKnmvExNOWK4dhBt9CUv1tayUuh2TVA7y/hZOz9IOZkNzpX2IvvZDNET7EZH7fOFdwKSHOW86NU nDWAjwWjBh6fGHns38+pI4wUg9zoYB0E95BUubrlSBHnr+UUrRqbLyMbGppQQuGW95N4XnhfFTXZ nA0sOGFxgG6CNGazWQwOtRlKzsOPmD1HND+y9BCKY= X-QQ-XMRINFO: NyFYKkN4Ny6FuXrnB5Ye7Aabb3ujjtK+gg== From: Edward Adam Davis To: syzbot+c473aa669b5e8a6f48d2@syzkaller.appspotmail.com Cc: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [mm?] possible deadlock in mfill_get_vma Date: Mon, 16 Mar 2026 08:57:30 +0800 X-OQ-MSGID: <20260316005729.119067-2-eadavis@qq.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <69b6fc68.a00a0220.3b25d1.001e.GAE@google.com> References: <69b6fc68.a00a0220.3b25d1.001e.GAE@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit #syz test diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 9ffc80d0a51b..ccfadea3dc79 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -197,7 +197,6 @@ static void mfill_put_vma(struct mfill_state *state) if (!state->vma) return; - up_read(&state->ctx->map_changing_lock); uffd_mfill_unlock(state->vma); state->vma = NULL; } @@ -261,6 +260,7 @@ static int mfill_get_vma(struct mfill_state *state) return 0; out_unlock: + up_read(&state->ctx->map_changing_lock); mfill_put_vma(state); return err; }