From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp153-166.sina.com.cn (smtp153-166.sina.com.cn [61.135.153.166]) (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 903FE1DF73A for ; Tue, 17 Mar 2026 22:45:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=61.135.153.166 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773787527; cv=none; b=dTNTs8do7fJwPFeMaa+pxLzB4J48Eem2bytxrEwHJMsWhpQtUYGh9DjbCFzRIYJBU5p/u1qHSy2wRzAlxVsw1jpc/sVUgJE8RXvKe4vqPTACcDhjSbWCPLcIW2+wrKVXQzdNnzJquBBq1BGkqRQ8CgvQ6hDXI4S9nNs+/Aw+7BI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773787527; c=relaxed/simple; bh=X9In2R5ukWZHpnG5EZzIJ7GuD6t1LUbD9GkkaFUH9B4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Ig1+3ZfojmYj8i6qxZrOqOANNnOCoa4dTFnhVFbOW+ppeby/zOxfyy8QNbYUcAp/1rDuUuaChiCM/F2+MjUylH2eOCWOd10liUlXducDqE+8T1egwrRxMMiI67CrTNOeEZLX4iSG6agp6JoORQNrV9kJQ1tQEvQAXFceU1SCKWE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sina.com; spf=pass smtp.mailfrom=sina.com; dkim=pass (1024-bit key) header.d=sina.com header.i=@sina.com header.b=NrtvfGbY; arc=none smtp.client-ip=61.135.153.166 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sina.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sina.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=sina.com header.i=@sina.com header.b="NrtvfGbY" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sina.com; s=201208; t=1773787520; bh=+Ur5skpg3jJqL5HVEqoJbKjqvSylAZPpGZAfqQrw/kk=; h=From:Subject:Date:Message-ID; b=NrtvfGbYWBfoGXV5rmbXYM4xjt+AIMCmfiyaFl5f7AsP5KDSMHOYKa1/J/ObYQ/Ee k9PBXA1Ihnq/GOs7juuy2joQTEb6nq/U1XQT09wH0oI4rFhS1lIe4PK0qWZGMmgzpC JnuoEI0IpI4oHDRQy+QIyQL3Qb47ap1VBUgBoWf8= X-SMAIL-HELO: localhost.localdomain Received: from unknown (HELO localhost.localdomain)([114.249.62.144]) by sina.com (10.54.253.33) with ESMTP id 69B9D97400004B27; Tue, 18 Mar 2026 06:45:11 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com Authentication-Results: sina.com; spf=none smtp.mailfrom=hdanton@sina.com; dkim=none header.i=none; dmarc=none action=none header.from=hdanton@sina.com X-SMAIL-MID: 6850606685243 X-SMAIL-UIID: E1111730D9F2474D9C817F945DDB3508-20260318-064511-1 From: Hillf Danton To: syzbot Cc: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [kernel?] WARNING in exit_mm Date: Wed, 18 Mar 2026 06:45:01 +0800 Message-ID: <20260317224501.1034-1-hdanton@sina.com> In-Reply-To: <69b9bbfc.050a0220.248e02.0151.GAE@google.com> References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit > Date: Tue, 17 Mar 2026 13:39:24 -0700 [thread overview] > Hello, > > syzbot found the following issue on: > > HEAD commit: b84a0ebe421c Add linux-next specific files for 20260313 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=15fb1602580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=e7280ad1f68b2dce > dashboard link: https://syzkaller.appspot.com/bug?extid=295a8715dd1bfadef8bf > compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=177918ba580000 #syz test --- x/kernel/locking/rwsem.c +++ y/kernel/locking/rwsem.c @@ -365,12 +365,11 @@ enum rwsem_wake_type { #define MAX_READERS_WAKEUP 0x100 static inline -bool __rwsem_del_waiter(struct rw_semaphore *sem, struct rwsem_waiter *waiter) +void __rwsem_del_waiter(struct rw_semaphore *sem, struct rwsem_waiter *waiter) __must_hold(&sem->wait_lock) { if (list_empty(&waiter->list)) { sem->first_waiter = NULL; - return true; } if (sem->first_waiter == waiter) { @@ -378,8 +377,6 @@ bool __rwsem_del_waiter(struct rw_semaph struct rwsem_waiter, list); } list_del(&waiter->list); - - return false; } /* @@ -394,7 +391,8 @@ static inline bool rwsem_del_waiter(struct rw_semaphore *sem, struct rwsem_waiter *waiter) { lockdep_assert_held(&sem->wait_lock); - if (__rwsem_del_waiter(sem, waiter)) + __rwsem_del_waiter(sem, waiter); + if (rwsem_is_contended(sem)) return true; atomic_long_andnot(RWSEM_FLAG_HANDOFF | RWSEM_FLAG_WAITERS, &sem->count); return false; --