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([111.198.231.89]) by newxmesmtplogicsvrszb43-0.qq.com (NewEsmtp) with SMTP id 6B723677; Sun, 19 Apr 2026 13:26:55 +0800 X-QQ-mid: xmsmtpt1776576415tqhe0ecpp Message-ID: X-QQ-XMAILINFO: NCJFlKxSknUZplNoNFIOVwqHMUyJ7u84KRjrvtdqcjZ8XuGm8L1JFEjaeQiQhB LGLsr0ps4f1VsQhwLJbXwhGVBJSF1M59JmfMC2R5cwV/dGn3NLAFb5I0LEsa7qc7yKt2ZG/a2i4h op7IqBQRxxEADiyXSpDNla0w+kbOoeNj+DI3R/Gkh860L0w4CxJhxZTQR1MhQT1L8N1CeHQtEArn lUJ8GhkpKRT4aHFsgLvfDKvcMT+Rt03BbIgHIgySXw0j+wVimBzz3GYmbBUORlw6RtnrtDgE3YCx JIt9J1/Ug4C9vPBW0+t0hfV2C0p08WNpxJaWYLxUSyJaLBylT00a0BUXLWTyosRJxQPLpVkc6DVY veuSrPvgsZsUcidP6IFSL3O22uuH42U7FY4xvl/bx2BmpW6w1/xSsbUoywLSZC3CkQvwxaGXkv8n OkaawdRVI2wWR/HH7CTwbgBuZScj+RzrWRe5KAWhZ7/rF6HafUtPg3vci+xrad7yo2waF9/Ilcv0 aK/G/M0VcHYb6jObXNiqJOC2n4jCJF+HGaJa77g6W/9pPIXHCTQt/W4ZAXRATCG7tEVhVPFhx3PT sMPcnvEAIFD3BsggqnTfDEnGrbd2MrhR5MF1de3afH7JR+SPHdBGNXemS8d1/E8GlBLG7Oas/ay6 QNMTNxgEY4HFnHPItwZqXT3bodRA8sYKraUa/fl9NwFyXs/jOdEntxh335Byg1n1a+CIkoYTwfLw 71Z5mO1KS7EG2OXg9EBgD9tAyHwd0nOtEvhEL6GeRtiVuqzAUHFD3din0pf64kfmZdqKnDzMZoP0 tazKgGK/9jgI/bs/+3XvZYynwfBqAljiYiueaFwpDgZkMdrlK8YzuS5QP+74BQmO9sRXG2RXLLuo lcGAFnKcmMzHUt0rADOfjELyFHEW0z71J6vbUfeftc5DxYDSjcB7+R6RLWo7Reu9AFG6ePcsmDT2 XcdOPfpx1UTf43Z2eqIcp40aZLsb+Rbt69iCzR/+mKcQRVRTH7rErxzdKHeviLbkBn/gqHmHkDya EsbmbPQBFfpP9vPh7D X-QQ-XMRINFO: MSVp+SPm3vtSI1QTLgDHQqIV1w2oNKDqfg== From: Edward Adam Davis To: syzbot+eede1fb91fb15bbbd5f2@syzkaller.appspotmail.com Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, miklos@szeredi.hu, syzkaller-bugs@googlegroups.com Subject: [PATCH next] fuse: avoid using the same file descriptor when cloning Date: Sun, 19 Apr 2026 13:26:56 +0800 X-OQ-MSGID: <20260419052655.496929-2-eadavis@qq.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <69e1934c.a70a0220.7229.0010.GAE@google.com> References: <69e1934c.a70a0220.7229.0010.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: quoted-printable Content-Type: text/plain; charset="utf-8" In fuse_dev_install_with_pq(), after updating the chan for the new device, the fch->connected value for the old device is set to 0. This logic is fundamentally flawed in cases where the new fd passed during a clone operation is identical to the device file's fd; specifically, during an unmount operation, this prevents fuse_conn_destroy() and subsequently fuse_chan_abort() from terminating pending requests, and the wake-up of the blocked_waitq is also consequently skipped. This triggers a timeout in fuse_chan_wait_aborted() [1]. The original conditional logic has been restored to correctly identify the new device file. [1] INFO: task syz-executor:5986 blocked for more than 143 seconds. Call Trace: fuse_chan_wait_aborted+0x15b/0x250 fs/fuse/dev.c:2212 fuse_conn_destroy+0x1e7/0x3e0 fs/fuse/inode.c:1969 fuse_sb_destroy fs/fuse/inode.c:1988 [inline] fuse_kill_sb_anon+0x1ef/0x270 fs/fuse/inode.c:2001 deactivate_locked_super+0xbc/0x130 fs/super.c:476 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312 Fixes: 88bf1f670f99 ("fuse: simplify fuse_dev_ioctl_clone()") Reported-by: syzbot+eede1fb91fb15bbbd5f2@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=3Deede1fb91fb15bbbd5f2 Tested-by: syzbot+eede1fb91fb15bbbd5f2@syzkaller.appspotmail.com Signed-off-by: Edward Adam Davis --- fs/fuse/dev.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 25c5c853a791..7c130656c4f6 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -2291,6 +2291,9 @@ static long fuse_dev_ioctl_clone(struct file *file, _= _u32 __user *argp) return -ENOMEM; =20 new_fud =3D fuse_file_to_fud(file); + if (fuse_dev_chan_get(new_fud)) + return -EINVAL; + if (!fuse_dev_install_with_pq(new_fud, fud->chan, pq)) return -EINVAL; =20 --=20 2.43.0