syzbot


WARNING in bpf_check (4)

Status: upstream: reported C repro on 2025/05/21 13:11
Subsystems: bpf
[Documentation on labels]
Reported-by: syzbot+0ef84a7bdf5301d4cbec@syzkaller.appspotmail.com
First crash: 41d, last: 32d
Discussions (2)
Title Replies (including bot) Last reply
[syzbot] [bpf?] WARNING in bpf_check (4) 1 (3) 2025/05/21 18:58
[PATCH bpf] bpf: verifier: support BPF_LOAD_ACQ in insn_def_regno() 1 (1) 2025/05/21 18:39
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in bpf_check (2) bpf C 9 2417d 2416d 11/29 fixed on 2018/12/07 08:24
upstream WARNING in bpf_check bpf 3 2536d 2542d 8/29 fixed on 2018/08/07 13:43
upstream WARNING in bpf_check (3) C done done 1736 1000d 1933d 22/29 fixed on 2023/02/24 13:50
Last patch testing requests (5)
Created Duration User Patch Repo Result
2025/06/09 18:46 25m retest repro upstream OK log
2025/06/09 18:46 24m retest repro upstream OK log
2025/06/09 18:46 24m retest repro upstream OK log
2025/06/09 18:46 25m retest repro upstream OK log
2025/05/21 18:31 25m puranjay@kernel.org patch upstream OK log

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 4151 at kernel/bpf/verifier.c:20723 opt_subreg_zext_lo32_rnd_hi32 kernel/bpf/verifier.c:20723 [inline]
WARNING: CPU: 1 PID: 4151 at kernel/bpf/verifier.c:20723 bpf_check+0x2d58/0x2ed4 kernel/bpf/verifier.c:24078
Modules linked in:
Kernel panic - not syncing: kernel: panic_on_warn set ...
CPU: 1 UID: 0 PID: 4151 Comm: syz.1.104 Not tainted 6.15.0-syzkaller #0 PREEMPT 
Hardware name: ARM-Versatile Express
Call trace: 
[<802019e4>] (dump_backtrace) from [<80201ae0>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:00000000 r6:828227fc r5:00000000 r4:82257fc0
[<80201ac8>] (show_stack) from [<8021ff7c>] (__dump_stack lib/dump_stack.c:94 [inline])
[<80201ac8>] (show_stack) from [<8021ff7c>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:120)
[<8021ff28>] (dump_stack_lvl) from [<8021ffbc>] (dump_stack+0x18/0x1c lib/dump_stack.c:129)
 r5:00000000 r4:82a70d4c
[<8021ffa4>] (dump_stack) from [<802025f8>] (panic+0x120/0x374 kernel/panic.c:354)
[<802024d8>] (panic) from [<802619e8>] (check_panic_on_warn kernel/panic.c:243 [inline])
[<802024d8>] (panic) from [<802619e8>] (get_taint+0x0/0x1c kernel/panic.c:238)
 r3:8280c604 r2:00000001 r1:8223eb8c r0:8224668c
 r7:804020d0
[<80261974>] (check_panic_on_warn) from [<80261b4c>] (__warn+0x80/0x188 kernel/panic.c:749)
[<80261acc>] (__warn) from [<80261dcc>] (warn_slowpath_fmt+0x178/0x1f4 kernel/panic.c:776)
 r8:00000009 r7:8225e4e0 r6:dfad1c44 r5:841f9800 r4:00000000
[<80261c58>] (warn_slowpath_fmt) from [<804020d0>] (opt_subreg_zext_lo32_rnd_hi32 kernel/bpf/verifier.c:20723 [inline])
[<80261c58>] (warn_slowpath_fmt) from [<804020d0>] (bpf_check+0x2d58/0x2ed4 kernel/bpf/verifier.c:24078)
 r10:00000004 r9:85478000 r8:00000006 r7:00000004 r6:00000003 r5:000000c3
 r4:ffffffff
[<803ff378>] (bpf_check) from [<803d66d0>] (bpf_prog_load+0x68c/0xc20 kernel/bpf/syscall.c:2971)
 r10:841f9800 r9:85496f30 r8:00000094 r7:dfad1d90 r6:00000000 r5:00000000
 r4:dfad1ec0
[<803d6044>] (bpf_prog_load) from [<803d7e24>] (__sys_bpf+0x578/0x1fd0 kernel/bpf/syscall.c:5834)
 r10:b5403587 r9:200003c0 r8:00000000 r7:00000000 r6:00000005 r5:dfad1e90
 r4:00000094
[<803d78ac>] (__sys_bpf) from [<803d9e1c>] (__do_sys_bpf kernel/bpf/syscall.c:5941 [inline])
[<803d78ac>] (__sys_bpf) from [<803d9e1c>] (sys_bpf+0x2c/0x48 kernel/bpf/syscall.c:5939)
 r10:00000182 r9:841f9800 r8:8020029c r7:00000182 r6:002e64c8 r5:00000000
 r4:00000000
[<803d9df0>] (sys_bpf) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:67)
Exception stack(0xdfad1fa8 to 0xdfad1ff0)
1fa0:                   00000000 00000000 00000005 200003c0 00000094 00000000
1fc0: 00000000 00000000 002e64c8 00000182 002d0000 00000000 00006364 76afa0bc
1fe0: 76af9ec0 76af9eb0 0001939c 00131f30
Rebooting in 86400 seconds..

Crashes (14):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/26 18:38 upstream 0ff41df1cb26 06877188 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm32 WARNING in bpf_check
2025/05/26 18:38 upstream 0ff41df1cb26 06877188 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm32 WARNING in bpf_check
2025/05/22 15:55 upstream d608703fcdd9 0919b50b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm32 WARNING in bpf_check
2025/05/22 15:55 upstream d608703fcdd9 0919b50b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm32 WARNING in bpf_check
2025/05/19 21:11 upstream a5806cd506af 8f9cf946 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm32 WARNING in bpf_check
2025/05/19 21:10 upstream a5806cd506af 8f9cf946 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm32 WARNING in bpf_check
2025/05/18 06:13 upstream 5723cc3450bc f41472b0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm32 WARNING in bpf_check
2025/05/18 06:12 upstream 5723cc3450bc f41472b0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm32 WARNING in bpf_check
2025/05/17 19:49 upstream 172a9d94339c f41472b0 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm32 WARNING in bpf_check
2025/05/17 18:19 upstream 172a9d94339c f41472b0 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm32 WARNING in bpf_check
2025/05/17 16:49 upstream 172a9d94339c f41472b0 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm32 WARNING in bpf_check
2025/05/17 15:16 upstream 172a9d94339c f41472b0 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm32 WARNING in bpf_check
2025/05/17 13:03 upstream 172a9d94339c f41472b0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm32 WARNING in bpf_check
2025/05/17 13:02 upstream 172a9d94339c f41472b0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm32 WARNING in bpf_check
* Struck through repros no longer work on HEAD.