UBSAN: shift-out-of-bounds in befs_check

Date	Name	Commit	Repro	Result
2025/12/20	upstream (ToT)	dd9b004b7ff3	C	[report] UBSAN: shift-out-of-bounds in befs_check_sb

Date

Name

Commit

Repro

Result

2025/12/20

upstream (ToT)

dd9b004b7ff3

[report] UBSAN: shift-out-of-bounds in befs_check_sb

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
linux-6.1	UBSAN: shift-out-of-bounds in befs_check_sb origin:upstream	-1	C		error	19	3d14h	871d	0/3	upstream: reported C repro on 2023/08/05 00:55
linux-5.15	UBSAN: shift-out-of-bounds in befs_check_sb origin:upstream	-1	C		error	16	3d14h	879d	0/3	upstream: reported C repro on 2023/07/28 00:42
upstream	UBSAN: shift-out-of-bounds in befs_check_sb fs	-1	C	error	done	79	3d08h	894d	0/29	upstream: reported C repro on 2023/07/12 13:47

syz.0.17[5926]: memfd_create() called without MFD_EXEC or MFD_NOEXEC_SEAL set loop0: detected capacity change from 0 to 128 ================================================================================ UBSAN: shift-out-of-bounds in fs/befs/super.c:96:9 shift exponent 2066842816 is too large for 32-bit type 'int' CPU: 0 PID: 5926 Comm: syz.0.17 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: <TASK> dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 ubsan_epilogue+0xa/0x30 lib/ubsan.c:217 __ubsan_handle_shift_out_of_bounds+0x380/0x400 lib/ubsan.c:387 befs_check_sb+0x419/0x4c0 fs/befs/super.c:96 befs_fill_super+0x8b2/0xe50 fs/befs/linuxvfs.c:873 mount_bdev+0x22b/0x2d0 fs/super.c:1643 legacy_get_tree+0xea/0x180 fs/fs_context.c:662 vfs_get_tree+0x8c/0x280 fs/super.c:1764 do_new_mount+0x24b/0xa40 fs/namespace.c:3386 do_mount fs/namespace.c:3726 [inline] __do_sys_mount fs/namespace.c:3935 [inline] __se_sys_mount+0x2da/0x3c0 fs/namespace.c:3912 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f81beb90eea Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff98e98d18 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fff98e98da0 RCX: 00007f81beb90eea RDX: 0000200000000040 RSI: 0000200000000000 RDI: 00007fff98e98d60 RBP: 0000200000000040 R08: 00007fff98e98da0 R09: 0000000000800001 R10: 0000000000800001 R11: 0000000000000246 R12: 0000200000000000 R13: 00007fff98e98d60 R14: 0000000000009e17 R15: 0000200000000080 </TASK> ================================================================================

Crashes (3):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2025/12/19 17:35	linux-6.6.y	5fa4793a2d2d	d6526ea3	.config	console log	report	syz / log	C		[disk image] [vmlinux] [kernel image] [mounted in repro]	ci2-linux-6-6-kasan	UBSAN: shift-out-of-bounds in befs_check_sb
2025/12/19 17:03	linux-6.6.y	5fa4793a2d2d	d6526ea3	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci2-linux-6-6-kasan	UBSAN: shift-out-of-bounds in befs_check_sb
2025/12/19 17:02	linux-6.6.y	5fa4793a2d2d	d6526ea3	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci2-linux-6-6-kasan	UBSAN: shift-out-of-bounds in befs_check_sb

Crashes (3):

Assets (help?)