kernel BUG in __open_session

Status: upstream: reported C repro on 2026/09/10 20:12
Subsystems: ceph
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+1dbed5969931c19d3eb5@syzkaller.appspotmail.com
First crash: 35d, last: 6h22m
Cause bisection: failed (error log, bisect log)
  
▶ ▼ ✨ AI Patch Versions (1)
Version Stage Reported Report Link Job
1 moderation 2026/09/11 00:20 Discussion 5cec5833-21da-4596-8bd4-1a3b1783fe0d
▶ ▼ ✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
ed537fdd assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ kernel BUG in __open_session 2026/09/11 00:24 2026/09/11 00:24 2026/09/11 01:08 1fe56c0a
5cec5833 patching ❓ kernel BUG in __open_session 2026/09/10 21:38 2026/09/10 21:38 2026/09/11 00:20 1fe56c0a
▶ ▼ Discussions (4)
Title Replies (including bot) Last reply
[PATCH] ceph: reject create client if no monitor 2 (2) 2026/09/11 14:01
[PATCH 2/2] ceph: don't keep a mon_addr= that failed to parse 1 (1) 2026/09/11 13:31
[PATCH 0/2] ceph: don't let a bad mon_addr= reach the empty-monmap BUG_ON() 2 (2) 2026/09/11 13:31
[syzbot] [ceph?] kernel BUG in __open_session 1 (3) 2026/09/11 13:23
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 kernel BUG in __open_session -1 syz, C 4 20d 20d 0/3 upstream: reported C repro on 2026/09/25 15:33
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2026/09/11 13:01 20m eadavis@sina.com patch git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 50d05c7c76c9 OK job log log
▶ ▼ Cause bisection attempts (2)
Created Duration User Patch Repo Result
2026/09/28 01:12 12h03m bisect upstream error job log
2026/09/20 20:44 0m bisect upstream error

Sample crash report:
libceph: resolve '1270.0.1' (ret=-3): failed
------------[ cut here ]------------
kernel BUG at net/ceph/mon_client.c:211!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 5603 Comm: syz-executor397 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:pick_new_mon net/ceph/mon_client.c:211 [inline]
RIP: 0010:__open_session+0x799/0x940 net/ceph/mon_client.c:245
Code: ca fd ff ff 44 89 e1 80 e1 07 38 c1 0f 8c d0 fd ff ff be 04 00 00 00 4c 89 e7 e8 a2 ad 1e f7 e9 be fd ff ff e8 58 b4 b2 f6 90 <0f> 0b 4d 89 ee 48 8b 04 24 42 0f b6 04 38 84 c0 0f 85 2f 01 00 00
RSP: 0018:ffffc90004bafae8 EFLAGS: 00010293
RAX: ffffffff8b1423d8 RBX: ffff88803ac4c308 RCX: ffff88803e8e1f40
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00000000ffffffff R08: ffff88803e8e1f40 R09: 0000000000000002
R10: 0000000000000100 R11: 0000000000000001 R12: 0000000000000000
R13: ffff88803ac4c470 R14: ffff88803ac4c310 R15: dffffc0000000000
FS:  000055558298b400(0000) GS:ffff888125bc2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000560e1b4567a0 CR3: 0000000043510000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 ceph_monc_open_session+0x56/0x1a0 net/ceph/mon_client.c:534
 __ceph_open_session+0x16d/0x5e0 net/ceph/ceph_common.c:798
 ceph_real_mount fs/ceph/super.c:1173 [inline]
 ceph_get_tree+0xafb/0x1a40 fs/ceph/super.c:1362
 vfs_get_tree+0x92/0x2a0 fs/super.c:1932
 vfs_cmd_create+0xa2/0x200 fs/fsopen.c:231
 __do_sys_fsconfig fs/fsopen.c:463 [inline]
 __se_sys_fsconfig+0x6bf/0x810 fs/fsopen.c:350
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f55a34fd589
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff0a4bbde8 EFLAGS: 00000246 ORIG_RAX: 00000000000001af
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f55a34fd589
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000003
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000006
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff0a4bbf58
R13: 431bde82d7b634db R14: 00007f55a3590c40 R15: 0000000000000002
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:pick_new_mon net/ceph/mon_client.c:211 [inline]
RIP: 0010:__open_session+0x799/0x940 net/ceph/mon_client.c:245
Code: ca fd ff ff 44 89 e1 80 e1 07 38 c1 0f 8c d0 fd ff ff be 04 00 00 00 4c 89 e7 e8 a2 ad 1e f7 e9 be fd ff ff e8 58 b4 b2 f6 90 <0f> 0b 4d 89 ee 48 8b 04 24 42 0f b6 04 38 84 c0 0f 85 2f 01 00 00
RSP: 0018:ffffc90004bafae8 EFLAGS: 00010293
RAX: ffffffff8b1423d8 RBX: ffff88803ac4c308 RCX: ffff88803e8e1f40
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00000000ffffffff R08: ffff88803e8e1f40 R09: 0000000000000002
R10: 0000000000000100 R11: 0000000000000001 R12: 0000000000000000
R13: ffff88803ac4c470 R14: ffff88803ac4c310 R15: dffffc0000000000
FS:  000055558298b400(0000) GS:ffff888125cc2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe74d23c74 CR3: 0000000043510000 CR4: 00000000003526f0

Crashes (107):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/04 07:11 upstream a74306e2e676 57bbd979 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-upstream-fs kernel BUG in __open_session
2026/10/04 06:29 upstream a74306e2e676 57bbd979 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-upstream-fs kernel BUG in __open_session
2026/09/20 19:20 upstream 518e5b794c06 853b104b .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-upstream-fs kernel BUG in __open_session
2026/09/10 19:03 upstream 50d05c7c76c9 1fe56c0a .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/09/30 23:38 upstream 551c722f4080 15fb8e5e .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 kernel BUG in __open_session
2026/10/14 23:26 upstream 4056b3c9d3c9 1a71827b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs kernel BUG in __open_session
2026/10/13 19:06 upstream 24a19b953e2a 5a1eeac4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs kernel BUG in __open_session
2026/10/05 10:46 upstream a90ee4305c4a 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs kernel BUG in __open_session
2026/10/05 08:09 upstream a90ee4305c4a 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs kernel BUG in __open_session
2026/10/05 00:16 upstream 6addb4f38557 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root kernel BUG in __open_session
2026/10/03 19:10 upstream e767a4ea70a3 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root kernel BUG in __open_session
2026/10/01 16:41 upstream 551c722f4080 38f7f0d1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root kernel BUG in __open_session
2026/10/01 02:13 upstream 551c722f4080 38f7f0d1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs kernel BUG in __open_session
2026/09/30 05:53 upstream 6f8319e3e9a4 7808aef4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root kernel BUG in __open_session
2026/09/28 22:44 upstream 72d3fcf802c4 a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs kernel BUG in __open_session
2026/09/26 11:40 upstream 6812ce4e4379 a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs kernel BUG in __open_session
2026/09/26 07:35 upstream 6812ce4e4379 a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs kernel BUG in __open_session
2026/10/16 02:49 upstream 045958acaa75 3f2522c6 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/14 15:45 upstream 4056b3c9d3c9 1a71827b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in __open_session
2026/10/14 01:07 upstream 24a19b953e2a 7321cd29 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/14 00:28 upstream 24a19b953e2a 7321cd29 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/13 14:57 upstream 24a19b953e2a 5a1eeac4 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in __open_session
2026/10/13 09:50 upstream 24a19b953e2a 5a1eeac4 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/12 16:11 upstream 24a19b953e2a 745a967f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/11 02:21 upstream a5ebb76233b7 4f92358f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/10 18:12 upstream 3857c2fe5449 4f92358f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/10 03:36 upstream 3857c2fe5449 4f92358f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/09 23:40 upstream af32da41b032 549ef7e3 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/09 05:16 upstream 6c377d19d4a5 b2734a59 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/08 02:47 upstream 7b63ef2d55f2 4f6a9fcf .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/07 10:01 upstream 602042bf29f6 6520ecdb .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/07 08:45 upstream 602042bf29f6 f7710056 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/07 05:12 upstream 69f80fef3153 f7710056 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/07 02:32 upstream 69f80fef3153 f7710056 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/06 15:46 upstream 2c3418fffa9d f7710056 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/06 14:12 upstream 2c3418fffa9d f7710056 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/06 13:12 upstream 2c3418fffa9d f7710056 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/06 03:39 upstream 67f0943b394d f7710056 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/05 21:29 upstream 67f0943b394d 1995e6c7 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/05 01:41 upstream 6addb4f38557 57bbd979 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/03 20:46 upstream e767a4ea70a3 57bbd979 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/02 10:11 upstream ce1e0223d8ad 1065c8fa .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/09/30 22:53 upstream 551c722f4080 15fb8e5e .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/09/30 17:28 upstream 551c722f4080 15fb8e5e .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/09/29 12:54 upstream 72d3fcf802c4 7bf4ea23 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/09/29 02:02 upstream 72d3fcf802c4 58f15308 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/09/27 06:53 upstream fd179f8a05be a3c7249d .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/09/26 23:19 upstream 6812ce4e4379 a3c7249d .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/09/26 08:43 upstream f14572c203d5 a3c7249d .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/09/26 03:56 upstream f14572c203d5 a3c7249d .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/09/25 19:23 upstream 165768bb7026 f281d9d2 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/09/25 02:38 upstream 5fc5768c7ca9 27d05fb3 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream kernel BUG in __open_session
2026/10/10 16:40 upstream 3857c2fe5449 4f92358f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 kernel BUG in __open_session
2026/10/10 10:43 upstream 3857c2fe5449 4f92358f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 kernel BUG in __open_session
2026/10/04 10:06 upstream a74306e2e676 57bbd979 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 kernel BUG in __open_session
2026/10/14 10:43 linux-next 1fffefb00cc0 7321cd29 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root kernel BUG in __open_session
2026/10/12 10:42 linux-next becb95e45ef0 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce kernel BUG in __open_session
2026/10/12 02:36 linux-next becb95e45ef0 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root kernel BUG in __open_session
* Struck through repros no longer work on HEAD.