WARNING in ring_buffer_map_get_reader (3)

Status: upstream: reported C repro on 2026/09/06 20:15
Subsystems: trace
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+de3d7f9bcc9212f3fae1@syzkaller.appspotmail.com
Fix commit: 89bab1dba8a0 ring-buffer: Fix false warning in ring_buffer_map_get_reader()
Patched on: [ci-qemu-gce-upstream-auto ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-snapshot-upstream-root ci-upstream-bpf-kasan-gce ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-linux-next-kasan-gce-root ci-upstream-rust-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce], missing on: [ci-qemu-native-arm64-kvm ci-qemu2-riscv64 ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-usb]
First crash: 50d, last: 3d09h
▶ ▼ ✨ AI Patch Versions (3)
Version Stage Reported Report Link Job
1 upstream 2026/09/18 14:33 Discussion 488adc18-a10e-42d2-a205-25327c38837f
2 moderation 2026/09/09 14:06 Discussion 488adc18-a10e-42d2-a205-25327c38837f
1 moderation 2026/09/08 11:48 Discussion f119d7de-b21d-4d27-b61e-5503e31edccd
▶ ▼ ✨ AI Jobs (6)
ID Workflow Result Correct Bug Created Started Finished Revision
27d311a5 patch-iteration ❓ WARNING in ring_buffer_map_get_reader (3) 2026/09/09 14:12 2026/09/09 14:12 2026/09/09 14:31 b31349d1
488adc18 patch-iteration ✅ WARNING in ring_buffer_map_get_reader (3) 2026/09/09 13:09 2026/09/09 13:09 2026/09/09 14:06 8387c273
f119d7de patching ❓ WARNING in ring_buffer_map_get_reader (3) 2026/09/08 10:00 2026/09/08 10:01 2026/09/08 11:48 680aa3e1
4853681e repro-c Reproduced: ✅ ❓ WARNING in ring_buffer_map_get_reader (3) 2026/09/07 17:18 2026/09/07 17:20 2026/09/07 17:37 680aa3e1
7ab64cc6 repro-c Reproduced: ✅ ❓ WARNING in ring_buffer_map_get_reader (3) 2026/09/07 11:44 2026/09/07 11:45 2026/09/07 12:00 4f7b22a0
7616afee assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ WARNING in ring_buffer_map_get_reader (3) 2026/09/04 05:12 2026/09/04 05:12 2026/09/04 05:38 801f0966
▶ ▼ Discussions (3)
Title Replies (including bot) Last reply
[for-linus][PATCH 09/16] ring-buffer: Fix false warning in ring_buffer_map_get_reader() 1 (1) 2026/10/15 13:33
[PATCH] ring-buffer: Fix false warning in ring_buffer_map_get_reader() 6 (6) 2026/09/24 09:06
[syzbot] [trace?] WARNING in ring_buffer_map_get_reader (3) 0 (3) 2026/09/10 11:48
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in ring_buffer_map_get_reader (2) prio:low trace -1 49 192d 283d 0/29 auto-obsoleted due to no activity on 2026/06/22 15:18
upstream WARNING in ring_buffer_map_get_reader trace -1 5 293d 351d 29/29 fixed on 2026/01/07 12:29
▶ ▼ Last patch testing requests (5)
Created Duration User Patch Repo Result
2026/09/21 18:10 13m retest repro upstream report job log log
2026/09/10 11:48 12m tahasami8@gmail.com patch upstream OK job log log
2026/09/07 17:43 12m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git df2908090cda368b01ff43709f51890076c56157 report job log log
2026/09/07 17:18 12m nogikh@google.com git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git df2908090cda368b01ff43709f51890076c56157 no crash job log log
2026/09/07 12:00 14m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git df2908090cda368b01ff43709f51890076c56157 no crash job log log

Sample crash report:
Ring buffer [0] commit overrun lost 3 events at timestamp:71798603963
------------[ cut here ]------------
!reader
WARNING: kernel/trace/ring_buffer.c:7998 at ring_buffer_map_get_reader+0x5f3/0x930 kernel/trace/ring_buffer.c:7998, CPU#1: syz-executor388/6024
Modules linked in:
CPU: 1 UID: 0 PID: 6024 Comm: syz-executor388 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:ring_buffer_map_get_reader+0x5f3/0x930 kernel/trace/ring_buffer.c:7998
Code: ff 48 89 df e8 be 22 fe ff 48 89 c5 e8 a6 88 fb ff 48 85 ed 0f 85 9f fc ff ff 4c 8b 74 24 58 4c 8b 7c 24 60 e8 8e 88 fb ff 90 <0f> 0b 90 e8 85 88 fb ff 49 8d bf d0 01 00 00 48 b8 00 00 00 00 00
RSP: 0018:ffffc90003977d98 EFLAGS: 00010093
RAX: 0000000000000000 RBX: ffff88801c0e5000 RCX: 0000000000000001
RDX: ffff8880333d4b00 RSI: ffffffff82108882 RDI: ffff8880333d4b00
RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: ffff88801c0e50b0 R12: ffff88801c0e50b8
R13: dffffc0000000000 R14: ffff88801c0e5198 R15: ffff88801c0ab800
FS:  00007f337024b6c0(0000) GS:ffff8880d5c5d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000559c2c45caa0 CR3: 000000003dec3000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 tracing_buffers_ioctl+0x2e6/0x3d0 kernel/trace/trace.c:7381
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3370a8136b
Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00
RSP: 002b:00007f337024b130 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f337024bcdc RCX: 00007f3370a8136b
RDX: 0000000000000000 RSI: 0000000000005220 RDI: 0000000000000004
RBP: 0000000000000021 R08: 0000000000000000 R09: 00007f337024b6c0
R10: 0000000000000008 R11: 0000000000000246 R12: ffffffffffffffd0
R13: 0000000000000000 R14: 00007ffc1cde9710 R15: 00007ffc1cde97f8
 </TASK>

Crashes (13):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/07 17:56 git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git df2908090cda 74e93e68 .config console log report C ci-qemu-upstream WARNING in ring_buffer_map_get_reader
2026/10/19 10:29 upstream f909e534f5e3 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in ring_buffer_map_get_reader
2026/10/16 10:57 upstream 2f2f7eeef8b0 b1757810 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in ring_buffer_map_get_reader
2026/10/16 05:13 upstream 2f2f7eeef8b0 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in ring_buffer_map_get_reader
2026/10/13 00:39 upstream 24a19b953e2a 745a967f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in ring_buffer_map_get_reader
2026/10/13 00:36 upstream 24a19b953e2a 745a967f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in ring_buffer_map_get_reader
2026/09/24 14:14 upstream 62f4c998b297 3c3cdf19 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in ring_buffer_map_get_reader
2026/10/03 23:25 upstream a74306e2e676 57bbd979 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in ring_buffer_map_get_reader
2026/09/26 07:19 upstream f14572c203d5 a3c7249d .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in ring_buffer_map_get_reader
2026/09/02 20:04 upstream 89a312991dc6 74e93e68 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in ring_buffer_map_get_reader
2026/09/28 07:35 linux-next f5f84daefcd9 a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ring_buffer_map_get_reader
2026/09/28 07:35 linux-next f5f84daefcd9 a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ring_buffer_map_get_reader
2026/09/28 06:05 linux-next f5f84daefcd9 a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in ring_buffer_map_get_reader
* Struck through repros no longer work on HEAD.