WARNING in ceph_con_v1_try_read

Status: upstream: reported C repro on 2026/08/03 22:36
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+5f2ad02c28da41099f8a@syzkaller.appspotmail.com
First crash: 6d23h, last: 1d09h
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2026/08/10 upstream (ToT) db2ddb871435 C [report] WARNING in ceph_con_v1_try_read
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 WARNING in ceph_con_v1_try_read -1 syz, C 11 6d09h 7d02h 0/3 upstream: reported C repro on 2026/08/03 19:06
linux-6.1 WARNING in ceph_con_v1_try_read -1 syz, C 16 7d00h 7d04h 0/3 upstream: reported C repro on 2026/08/03 17:32
upstream WARNING in ceph_con_v1_try_read ceph prio:high -1 syz, C 52 6d13h 3d07h 0/29 upstream: reported C repro on 2026/08/07 14:37

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 3065 at include/linux/ceph/decode.h:238 ceph_decode_banner_addr include/linux/ceph/decode.h:238 [inline]
WARNING: CPU: 1 PID: 3065 at include/linux/ceph/decode.h:238 read_partial_banner net/ceph/messenger_v1.c:636 [inline]
WARNING: CPU: 1 PID: 3065 at include/linux/ceph/decode.h:238 ceph_con_v1_try_read+0x5c08/0x6400 net/ceph/messenger_v1.c:1343
Modules linked in:
CPU: 1 PID: 3065 Comm: kworker/1:2 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: ceph-msgr ceph_con_workfn
RIP: 0010:ceph_decode_banner_addr include/linux/ceph/decode.h:238 [inline]
RIP: 0010:read_partial_banner net/ceph/messenger_v1.c:636 [inline]
RIP: 0010:ceph_con_v1_try_read+0x5c08/0x6400 net/ceph/messenger_v1.c:1343
Code: c4 08 49 8d 5d 30 48 89 d8 48 c1 e8 03 42 80 3c 38 00 0f 84 95 01 00 00 48 89 df e8 e2 7a 93 f7 e9 88 01 00 00 e8 c8 f7 3a f7 <0f> 0b e9 65 f4 ff ff e8 bc f7 3a f7 48 c7 c7 60 0d e6 8b 44 89 fe
RSP: 0018:ffffc9000c3771c0 EFLAGS: 00010293
RAX: ffffffff8a4c79b8 RBX: dffffc0000000000 RCX: ffff88802c2a8000
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000002
RBP: ffffc9000c377b38 R08: ffffc9000c37700f R09: 0000000000000000
R10: ffffc9000c377000 R11: fffff5200186ee02 R12: 0000000000000002
R13: 0000000000000200 R14: fffff5200186ee74 R15: ffff88807982077a
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcb207e8ff8 CR3: 0000000076c1a000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 ceph_con_workfn+0x205/0x1250 net/ceph/messenger.c:1576
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/09 12:51 linux-6.6.y 6436c12a2ced 5d63f80b .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in ceph_con_v1_try_read
2026/08/03 22:40 linux-6.6.y aa0e49877a2e 6b7c9f71 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in ceph_con_v1_try_read
2026/08/03 22:39 linux-6.6.y aa0e49877a2e 6b7c9f71 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in ceph_con_v1_try_read
2026/08/03 22:37 linux-6.6.y aa0e49877a2e 6b7c9f71 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in ceph_con_v1_try_read
2026/08/03 22:36 linux-6.6.y aa0e49877a2e 6b7c9f71 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in ceph_con_v1_try_read
2026/08/03 22:36 linux-6.6.y aa0e49877a2e 6b7c9f71 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in ceph_con_v1_try_read
* Struck through repros no longer work on HEAD.