linux-kernel - [syzbot] [bpf?] WARNING in bpf

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Message-ID: <682dd10b.a00a0220.29bc26.028e.GAE@google.com>
Date: Wed, 21 May 2025 06:11:39 -0700
From: syzbot <syzbot+0ef84a7bdf5301d4cbec@...kaller.appspotmail.com>
To: andrii@...nel.org, ast@...nel.org, bpf@...r.kernel.org, 
	daniel@...earbox.net, eddyz87@...il.com, haoluo@...gle.com, 
	john.fastabend@...il.com, jolsa@...nel.org, kpsingh@...nel.org, 
	linux-kernel@...r.kernel.org, martin.lau@...ux.dev, sdf@...ichev.me, 
	song@...nel.org, syzkaller-bugs@...glegroups.com, yonghong.song@...ux.dev
Subject: [syzbot] [bpf?] WARNING in bpf_check (4)

Hello,

syzbot found the following issue on:

HEAD commit:    172a9d94339c Merge tag '6.15-rc6-smb3-client-fixes' of git..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11d15ef4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4f080d149583fe67
dashboard link: https://syzkaller.appspot.com/bug?extid=0ef84a7bdf5301d4cbec
compiler:       arm-linux-gnueabi-gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=130462d4580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14efaef4580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/98a89b9f34e4/non_bootable_disk-172a9d94.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/88f3b6a8815a/vmlinux-172a9d94.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8835063aa13d/zImage-172a9d94.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0ef84a7bdf5301d4cbec@...kaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 1 PID: 3102 at kernel/bpf/verifier.c:20723 opt_subreg_zext_lo32_rnd_hi32 kernel/bpf/verifier.c:20723 [inline]
WARNING: CPU: 1 PID: 3102 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: 3102 Comm: syz-executor107 Not tainted 6.15.0-rc6-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 r4:82257e84
[<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 r1:8223ea4c r0:8224654c
 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 r7:8225e3a4 r6:df989c44 r5:844f0000 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)
 r10:00000002 r9:84850000 r8:00000004 r7:00000002 r6:00000003 r5:000000c3
 r4:ffffffff
[<803ff378>] (bpf_check) from [<803d66d0>] (bpf_prog_load+0x68c/0xc20 kernel/bpf/syscall.c:2971)
 r10:844f0000 r9:842a6f30 r8:00000048 r7:df989d90 r6:00000000 r5:00000000
 r4:df989ec0
[<803d6044>] (bpf_prog_load) from [<803d7e24>] (__sys_bpf+0x578/0x1fd0 kernel/bpf/syscall.c:5834)
 r10:b5403587 r9:2000e000 r8:00000000 r7:00000000 r6:00000005 r5:df989e90
 r4:00000048
[<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 r9:844f0000 r8:8020029c r7:00000182 r6:0008e048 r5:00000000
 r4:ffffffff
[<803d9df0>] (sys_bpf) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:67)
Exception stack(0xdf989fa8 to 0xdf989ff0)
9fa0:                   ffffffff 00000000 00000005 2000e000 00000048 00000000
9fc0: ffffffff 00000000 0008e048 00000182 00000002 0000fd90 000f4240 00000000
9fe0: 7ebc8c70 7ebc8c60 000106bc 0002e810
Rebooting in 86400 seconds..


---
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