From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 35F2D30DEC1; Wed, 28 Jan 2026 15:56:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769615786; cv=none; b=uBLvCnZ6hF2eAZf3sj4lZY3OxvarJXYwu1vwOulWkvey9YcV3PC+MQIOQS+aENO5Oc71t5E93/8ILss01LNe0aCb4ZVo0CqLaRmwasfDc3Zl6n78oClM9DOOEL0gxJlkSezlsFpamEtkkeCfMPO8mK/yeh1pS2inW6y7WKgKCsw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769615786; c=relaxed/simple; bh=p7aiI6JJbde5Vj5CAOBcQAdh5TCULluEFqW0cUJtrPM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cOAv9w5TM1BhBQw7fIRc4avVZbMzkDmzDTXHsT/OX5y15higm2j04YwzOopTvAAON/AQiC85o1leg+fjoYyrpS5GRQZCT1n1FzhImb9NJHtMJQfY0hLmwGa0QUjZqzdxLZtEdQ8mxkP44H4FbdfjSVmtXeJd8hMC2k+gkwCc5ig= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=DArzugnk; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="DArzugnk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 615D5C16AAE; Wed, 28 Jan 2026 15:56:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1769615785; bh=p7aiI6JJbde5Vj5CAOBcQAdh5TCULluEFqW0cUJtrPM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DArzugnkjq0ElenKWjXfLY9qc2dkadg0wi4W8aq9aH69wG4MYXiXcA6ujCtMtlXvS KdTeEv+e+xrJvWV3p1krNz49PeNHWl4qusqYLdWDlgIgOZLYfrHrB9odJ/tSV9tfUN hrUKXYmlUte/Q+kpEykHnxQGx8GNg0dtY0Ldl+Vo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot , Eric Dumazet , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.18 114/227] mISDN: annotate data-race around dev->work Date: Wed, 28 Jan 2026 16:22:39 +0100 Message-ID: <20260128145348.568212770@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260128145344.331957407@linuxfoundation.org> References: <20260128145344.331957407@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 8175dbf174d487afab81e936a862a8d9b8a1ccb6 ] dev->work can re read locklessly in mISDN_read() and mISDN_poll(). Add READ_ONCE()/WRITE_ONCE() annotations. BUG: KCSAN: data-race in mISDN_ioctl / mISDN_read write to 0xffff88812d848280 of 4 bytes by task 10864 on cpu 1: misdn_add_timer drivers/isdn/mISDN/timerdev.c:175 [inline] mISDN_ioctl+0x2fb/0x550 drivers/isdn/mISDN/timerdev.c:233 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xce/0x140 fs/ioctl.c:583 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583 x64_sys_call+0x14b0/0x3000 arch/x86/include/generated/asm/syscalls_64.h:17 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd8/0x2c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffff88812d848280 of 4 bytes by task 10857 on cpu 0: mISDN_read+0x1f2/0x470 drivers/isdn/mISDN/timerdev.c:112 do_loop_readv_writev fs/read_write.c:847 [inline] vfs_readv+0x3fb/0x690 fs/read_write.c:1020 do_readv+0xe7/0x210 fs/read_write.c:1080 __do_sys_readv fs/read_write.c:1165 [inline] __se_sys_readv fs/read_write.c:1162 [inline] __x64_sys_readv+0x45/0x50 fs/read_write.c:1162 x64_sys_call+0x2831/0x3000 arch/x86/include/generated/asm/syscalls_64.h:20 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd8/0x2c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0x00000000 -> 0x00000001 Fixes: 1b2b03f8e514 ("Add mISDN core files") Reported-by: syzbot Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260118132528.2349573-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/isdn/mISDN/timerdev.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/drivers/isdn/mISDN/timerdev.c b/drivers/isdn/mISDN/timerdev.c index df98144a95394..33521c328a827 100644 --- a/drivers/isdn/mISDN/timerdev.c +++ b/drivers/isdn/mISDN/timerdev.c @@ -109,14 +109,14 @@ mISDN_read(struct file *filep, char __user *buf, size_t count, loff_t *off) spin_unlock_irq(&dev->lock); if (filep->f_flags & O_NONBLOCK) return -EAGAIN; - wait_event_interruptible(dev->wait, (dev->work || + wait_event_interruptible(dev->wait, (READ_ONCE(dev->work) || !list_empty(list))); if (signal_pending(current)) return -ERESTARTSYS; spin_lock_irq(&dev->lock); } if (dev->work) - dev->work = 0; + WRITE_ONCE(dev->work, 0); if (!list_empty(list)) { timer = list_first_entry(list, struct mISDNtimer, list); list_del(&timer->list); @@ -141,13 +141,16 @@ mISDN_poll(struct file *filep, poll_table *wait) if (*debug & DEBUG_TIMER) printk(KERN_DEBUG "%s(%p, %p)\n", __func__, filep, wait); if (dev) { + u32 work; + poll_wait(filep, &dev->wait, wait); mask = 0; - if (dev->work || !list_empty(&dev->expired)) + work = READ_ONCE(dev->work); + if (work || !list_empty(&dev->expired)) mask |= (EPOLLIN | EPOLLRDNORM); if (*debug & DEBUG_TIMER) printk(KERN_DEBUG "%s work(%d) empty(%d)\n", __func__, - dev->work, list_empty(&dev->expired)); + work, list_empty(&dev->expired)); } return mask; } @@ -172,7 +175,7 @@ misdn_add_timer(struct mISDNtimerdev *dev, int timeout) struct mISDNtimer *timer; if (!timeout) { - dev->work = 1; + WRITE_ONCE(dev->work, 1); wake_up_interruptible(&dev->wait); id = 0; } else { -- 2.51.0