UBSAN: shift-out-of-bounds in gfs2_dir_read

Status: upstream: reported C repro on 2025/07/15 02:48
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+f1fa2e48b9372b638fee@syzkaller.appspotmail.com
First crash: 388d, last: 82d
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2025/07/15 upstream (ToT) 155a3c003e55 C [report] UBSAN: shift-out-of-bounds in gfs2_dir_read
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream UBSAN: shift-out-of-bounds in gfs2_dir_read gfs2 -1 1 587d 583d 0/29 auto-obsoleted due to no activity on 2025/04/06 22:03
upstream UBSAN: shift-out-of-bounds in gfs2_dir_read (2) gfs2 -1 syz, C 13 385d 389d 29/29 fixed on 2025/09/04 16:57
linux-6.1 UBSAN: shift-out-of-bounds in gfs2_dir_read origin:upstream missing-backport -1 syz, C inconclusive 8 227d 388d 0/3 upstream: reported C repro on 2025/07/15 01:59
▶ ▼ Last patch testing requests (10)
Created Duration User Patch Repo Result
2026/07/26 15:28 24m retest repro linux-5.15.y report log
2026/07/26 15:28 22m retest repro linux-5.15.y report log
2026/07/26 15:28 22m retest repro linux-5.15.y report log
2026/07/26 15:28 23m retest repro linux-5.15.y report log
2026/07/09 15:21 24m retest repro linux-5.15.y report log
2026/05/16 23:44 50m retest repro linux-5.15.y report log
2026/05/16 23:44 45m retest repro linux-5.15.y report log
2026/05/16 23:44 19m retest repro linux-5.15.y report log
2026/05/16 23:44 16m retest repro linux-5.15.y report log
2026/04/06 09:47 21m retest repro linux-5.15.y report log

Sample crash report:
gfs2: fsid=syz:syz.s: journal 0 mapped with 5 extents in 0ms
gfs2: fsid=syz:syz.s: first mount done, others may mount
================================================================================
UBSAN: shift-out-of-bounds in fs/gfs2/dir.c:1542:15
shift exponent 32 is too large for 32-bit type 'u32' (aka 'unsigned int')
CPU: 1 PID: 4165 Comm: syz.0.16 Not tainted 5.15.188-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call trace:
 dump_backtrace+0x0/0x43c arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf8/0x160 lib/dump_stack.c:106
 dump_stack+0x1c/0x5c lib/dump_stack.c:113
 ubsan_epilogue+0x14/0x48 lib/ubsan.c:151
 __ubsan_handle_shift_out_of_bounds+0x2b4/0x358 lib/ubsan.c:321
 dir_e_read fs/gfs2/dir.c:1542 [inline]
 gfs2_dir_read+0x1348/0x138c fs/gfs2/dir.c:1583
 gfs2_readdir+0x134/0x194 fs/gfs2/file.c:115
 iterate_dir+0x1f0/0x4cc fs/readdir.c:-1
 __do_sys_getdents64 fs/readdir.c:369 [inline]
 __se_sys_getdents64 fs/readdir.c:354 [inline]
 __arm64_sys_getdents64+0x11c/0x340 fs/readdir.c:354
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
================================================================================
gfs2: fsid=syz:syz.s: fatal: filesystem consistency error
  inode = 12 2341
  function = gfs2_dir_get_hash_table, file = fs/gfs2/dir.c, line = 350
gfs2: fsid=syz:syz.s: about to withdraw this file system
gfs2: fsid=syz:syz.s: Journal recovery skipped for jid 0 until next mount.
gfs2: fsid=syz:syz.s: Glock dequeues delayed: 0
gfs2: fsid=syz:syz.s: File system withdrawn
CPU: 0 PID: 4165 Comm: syz.0.16 Not tainted 5.15.188-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call trace:
 dump_backtrace+0x0/0x43c arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf8/0x160 lib/dump_stack.c:106
 dump_stack+0x1c/0x5c lib/dump_stack.c:113
 gfs2_withdraw+0xc60/0x129c fs/gfs2/util.c:355
 gfs2_consist_inode_i+0xcc/0xe8 fs/gfs2/util.c:456
 gfs2_dir_get_hash_table+0x194/0x830 fs/gfs2/dir.c:350
 dir_e_read fs/gfs2/dir.c:1546 [inline]
 gfs2_dir_read+0x2b8/0x138c fs/gfs2/dir.c:1583
 gfs2_readdir+0x134/0x194 fs/gfs2/file.c:115
 iterate_dir+0x1f0/0x4cc fs/readdir.c:-1
 __do_sys_getdents64 fs/readdir.c:369 [inline]
 __se_sys_getdents64 fs/readdir.c:354 [inline]
 __arm64_sys_getdents64+0x11c/0x340 fs/readdir.c:354
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/15 19:58 linux-5.15.y 89950c454265 03fcfc4b .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-5-15-kasan-arm64 UBSAN: shift-out-of-bounds in gfs2_dir_read
2025/07/15 19:32 linux-5.15.y 89950c454265 03fcfc4b .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-5-15-kasan-arm64 UBSAN: shift-out-of-bounds in gfs2_dir_read
2025/07/15 18:54 linux-5.15.y 89950c454265 03fcfc4b .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-5-15-kasan-arm64 UBSAN: shift-out-of-bounds in gfs2_dir_read
2025/07/15 18:27 linux-5.15.y 89950c454265 03fcfc4b .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-5-15-kasan-arm64 UBSAN: shift-out-of-bounds in gfs2_dir_read
2025/07/15 17:57 linux-5.15.y 89950c454265 03fcfc4b .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-5-15-kasan-arm64 UBSAN: shift-out-of-bounds in gfs2_dir_read
2025/07/18 16:31 linux-5.15.y c79648372d02 88248e14 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan UBSAN: shift-out-of-bounds in gfs2_dir_read
2025/07/18 16:29 linux-5.15.y c79648372d02 88248e14 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan UBSAN: shift-out-of-bounds in gfs2_dir_read
2025/07/15 02:48 linux-5.15.y 89950c454265 d8fc7335 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 UBSAN: shift-out-of-bounds in gfs2_dir_read
2025/07/15 02:47 linux-5.15.y 89950c454265 d8fc7335 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 UBSAN: shift-out-of-bounds in gfs2_dir_read
* Struck through repros no longer work on HEAD.