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general protection fault in ovl_iterate

Status: upstream: reported C repro on 2025/12/23 14:44
Subsystems: overlayfs
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+a16fb0cce329a320661c@syzkaller.appspotmail.com
Fix commit: 1711b6ed6953 ovl: keep err zero after successful ovl_cache_get()
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-arm64 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-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci-upstream-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce 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 ci2-upstream-usb]
First crash: 181d, last: 9d01h
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
39eea396-bc44-4197-a9e9-e441626aa98b assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ general protection fault in ovl_iterate 2026/05/25 02:18 2026/05/25 02:18 2026/05/25 02:40 c69befb30ac10e158cc9d1557b508ee3f0eca1de
▶ ▼ Discussions (6)
Title Replies (including bot) Last reply
[PATCH] ovl: keep err zero after successful ovl_cache_get() 11 (11) 2026/05/18 12:57
Re: [RFC PATCH] ovl: keep merged and impure readdir caches separate 2 (2) 2026/05/14 21:16
[RFC PATCH] ovl: keep merged and impure readdir caches separate 6 (6) 2026/05/14 13:09
[syzbot] Monthly overlayfs report (Jan 2026) 0 (1) 2026/01/28 12:41
[syzbot] Monthly overlayfs report (Dec 2025) 0 (1) 2025/12/28 08:47
[syzbot] [overlayfs?] general protection fault in ovl_iterate 0 (2) 2025/12/23 16:12
▶ ▼ Last patch testing requests (2)
Created Duration User Patch Repo Result
2026/04/12 17:23 24m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci error
2026/02/01 10:47 27m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci error

Sample crash report:
Unable to handle kernel paging request at virtual address ffffffffc24a9a90
KASAN: maybe wild-memory-access in range [0x0003fffe1254d480-0x0003fffe1254d487]
Mem abort info:
  ESR = 0x0000000096000006
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x06: level 2 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000
  CM = 0, WnR = 0, TnD = 0, TagAccess = 0
  GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000206d55000
[ffffffffc24a9a90] pgd=0000000000000000, p4d=000000020aaef403, pud=000000020aaf0403, pmd=0000000000000000
Internal error: Oops: 0000000096000006 [#1]  SMP
Modules linked in:
CPU: 0 UID: 0 PID: 6752 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : ovl_seek_cursor fs/overlayfs/readdir.c:471 [inline]
pc : ovl_iterate_merged fs/overlayfs/readdir.c:851 [inline]
pc : ovl_iterate+0xff8/0x1ca4 fs/overlayfs/readdir.c:906
lr : ovl_cache_get fs/overlayfs/readdir.c:505 [inline]
lr : ovl_iterate_merged fs/overlayfs/readdir.c:845 [inline]
lr : ovl_iterate+0xcbc/0x1ca4 fs/overlayfs/readdir.c:906
sp : ffff80009d567860
x29: ffff80009d567b70 x28: ffff0000c24a9e80 x27: 0000000000000000
x26: 0000000000000000 x25: ffffffffc24a9a80 x24: ffff0000c24a9e88
x23: ffffffffc24a9a90 x22: ffff80009d567cc8 x21: dfff800000000000
x20: ffff0000d55a1a5c x19: ffffffffc24a9a90 x18: 00000000ffffffff
x17: ffff800080df1c30 x16: ffff80008053826c x15: 0000000000000001
x14: 00000000ffff8000 x13: 0000000074bfa048 x12: ffff800080021d9c
x11: ffff800093397d48 x10: 0000000000ff0100 x9 : 860a1b99182b4800
x8 : 0000000000000000 x7 : 0000000000000000 x6 : 000000000000003f
x5 : 0000000000000040 x4 : 0000000000000001 x3 : 0000000000000010
x2 : 0000000000000006 x1 : 0000000000000080 x0 : 0000000000000001
Call trace:
 ovl_seek_cursor fs/overlayfs/readdir.c:471 [inline] (P)
 ovl_iterate_merged fs/overlayfs/readdir.c:851 [inline] (P)
 ovl_iterate+0xff8/0x1ca4 fs/overlayfs/readdir.c:906 (P)
 wrap_directory_iterator+0x90/0xf0 fs/readdir.c:65
 shared_ovl_iterate+0x30/0x40 fs/overlayfs/readdir.c:1065
 iterate_dir+0x2dc/0x478 fs/readdir.c:108
 __do_sys_getdents64 fs/readdir.c:410 [inline]
 __se_sys_getdents64 fs/readdir.c:396 [inline]
 __arm64_sys_getdents64+0x110/0x2fc fs/readdir.c:396
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x5c/0x26c arch/arm64/kernel/entry-common.c:724
 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
Code: 38756908 34000068 aa1703e0 97c3a4c7 (f94002f7) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	38756908 	ldrb	w8, [x8, x21]
   4:	34000068 	cbz	w8, 0x10
   8:	aa1703e0 	mov	x0, x23
   c:	97c3a4c7 	bl	0xffffffffff0e9328
* 10:	f94002f7 	ldr	x23, [x23] <-- trapping instruction

Crashes (20):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/23 16:11 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 8f0b4cce4481 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: unable to handle kernel paging request in ovl_iterate
2026/03/19 14:41 upstream 8a30aeb0d1b4 bd6dcb30 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in ovl_iterate
2026/01/18 03:17 upstream d3eeb99bbc99 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root general protection fault in ovl_iterate
2025/12/16 07:53 upstream 8f0b4cce4481 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in ovl_iterate
2025/12/15 20:44 upstream 8f0b4cce4481 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root general protection fault in ovl_iterate
2025/12/16 08:08 upstream 8f0b4cce4481 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root BUG: unable to handle kernel paging request in ovl_iterate
2025/12/16 07:54 upstream 8f0b4cce4481 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root BUG: unable to handle kernel paging request in ovl_iterate
2026/06/06 18:14 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci ffe7bef3786c cc095639 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: unable to handle kernel paging request in ovl_iterate
2026/05/26 17:46 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 4b4362973b6f a3e47276 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: unable to handle kernel paging request in ovl_iterate
2026/05/24 06:26 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 4b4362973b6f c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: unable to handle kernel paging request in ovl_iterate
2026/05/22 05:02 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 4b4362973b6f e195359d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: unable to handle kernel paging request in ovl_iterate
2026/05/15 05:19 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 5cbb61bf4168 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: unable to handle kernel paging request in ovl_iterate
2026/05/06 22:22 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 5cbb61bf4168 cbcd9ea0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: unable to handle kernel paging request in ovl_iterate
2026/02/07 11:54 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 59e4d31a0470 f20fc9f9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: unable to handle kernel paging request in ovl_iterate
2026/01/07 16:56 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci e8c40f11c7b0 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: unable to handle kernel paging request in ovl_iterate
2026/01/07 11:22 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci e8c40f11c7b0 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: unable to handle kernel paging request in ovl_iterate
2025/12/27 09:33 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 8f0b4cce4481 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: unable to handle kernel paging request in ovl_iterate
2025/12/26 19:42 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 8f0b4cce4481 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: unable to handle kernel paging request in ovl_iterate
2025/12/26 09:46 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 8f0b4cce4481 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: unable to handle kernel paging request in ovl_iterate
2025/12/23 14:43 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 8f0b4cce4481 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: unable to handle kernel paging request in ovl_iterate
* Struck through repros no longer work on HEAD.