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KASAN: vmalloc-out-of-bounds Read in fanotify_read

Status: moderation: reported on 2026/06/27 12:32
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+9cffbbb502957f124c89@syzkaller.appspotmail.com
First crash: 6d12h, last: 6d12h
▶ ▼ ✨ AI Jobs (3)
ID Workflow Result Correct Bug Created Started Finished Revision Error
c8b71416-c99c-4e98-8a57-f25aedeaf84c assessment-security 💥 KASAN: vmalloc-out-of-bounds Read in fanotify_read 2026/06/30 00:00 2026/06/30 00:00 2026/06/30 00:00 fff8d0a0e302881e84edbe2230016e3bec252ec6 
failed to run ["git" "-c" "core.hooksPath=/dev/null" "checkout" "92e3f6ef4ffb1f65e7774f4611c27fb764b3bc14"]: exit status 128
error: Could not read 23997b17256ca0184953e2c4954dccb29b175f37
21ce7bfe-c953-497b-8e05-9bfc1274d2be assessment-security 💥 KASAN: vmalloc-out-of-bounds Read in fanotify_read 2026/06/27 00:00 2026/06/27 00:00 2026/06/27 00:00 7ff32d8bb9773a5f02d3db4c8207fc9251ebedc5 
failed to run ["git" "-c" "core.hooksPath=/dev/null" "checkout" "92e3f6ef4ffb1f65e7774f4611c27fb764b3bc14"]: exit status 128
fatal: unable to read tree (8c0e9110d5746386621b881b9e72384d6faee05d)
4728fea9-35b1-4c1e-8f24-86b0e76c983f assessment-security 💥 KASAN: vmalloc-out-of-bounds Read in fanotify_read 2026/06/25 00:00 2026/06/25 00:00 2026/06/25 00:00 2e5297c5126f27e51eeef9157f2111c5beb11e4f 
failed to run ["git" "-c" "core.hooksPath=/dev/null" "fetch" "--force" "--tags" "433dfd5a8a5d80bbf0669b14e9ed908911a52dd6" "92e3f6ef4ffb1f65e7774f4611c27fb764b3bc14"]: exit status 128
error: insuffici...
truncated to first 200 bytes; open job for full error
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: stack-out-of-bounds Read in fanotify_read fs 17 1 475d 471d 0/29 auto-obsoleted due to no activity on 2025/06/09 03:57

Sample crash report:
==================================================================
BUG: KASAN: vmalloc-out-of-bounds in copy_range_info_to_user fs/notify/fanotify/fanotify_user.c:682 [inline]
BUG: KASAN: vmalloc-out-of-bounds in copy_info_records_to_user fs/notify/fanotify/fanotify_user.c:813 [inline]
BUG: KASAN: vmalloc-out-of-bounds in copy_event_to_user fs/notify/fanotify/fanotify_user.c:944 [inline]
BUG: KASAN: vmalloc-out-of-bounds in fanotify_read+0x13d8/0x23a4 fs/notify/fanotify/fanotify_user.c:1032
Read of size 8 at addr ffff800092bb7b08 by task syz.6.1374/10180

CPU: 0 UID: 0 PID: 10180 Comm: syz.6.1374 Tainted: G             L      syzkaller #0 PREEMPT 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/02/2026
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 print_address_description+0xb0/0x238 mm/kasan/report.c:378
 print_report+0x68/0x84 mm/kasan/report.c:482
 kasan_report+0x8c/0xc4 mm/kasan/report.c:595
 __asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381
 copy_range_info_to_user fs/notify/fanotify/fanotify_user.c:682 [inline]
 copy_info_records_to_user fs/notify/fanotify/fanotify_user.c:813 [inline]
 copy_event_to_user fs/notify/fanotify/fanotify_user.c:944 [inline]
 fanotify_read+0x13d8/0x23a4 fs/notify/fanotify/fanotify_user.c:1032
 do_loop_readv_writev+0x24c/0x3dc fs/read_write.c:-1
 vfs_readv+0x258/0x520 fs/read_write.c:1022
 do_readv+0x134/0x2a8 fs/read_write.c:1082
 __do_sys_readv fs/read_write.c:1167 [inline]
 __se_sys_readv fs/read_write.c:1164 [inline]
 __arm64_sys_readv+0x80/0x94 fs/read_write.c:1164
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736
 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594

The buggy address belongs to a vmalloc virtual mapping
Memory state around the buggy address:
 ffff800092bb7a00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffff800092bb7a80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>ffff800092bb7b00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                      ^
 ffff800092bb7b80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffff800092bb7c00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================
Unable to handle kernel paging request at virtual address ffff800092bb7b08
KASAN: probably user-memory-access in range [0x0000000495dbd840-0x0000000495dbd847]
Mem abort info:
  ESR = 0x0000000096000007
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x07: level 3 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000007, 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=000000021b33c000
[ffff800092bb7b08] pgd=0000000000000000, p4d=10000002215ef003, pud=10000002215f0003, pmd=10000001051dd403, pte=0000000000000000
Internal error: Oops: 0000000096000007 [#1]  SMP
Modules linked in:
CPU: 0 UID: 0 PID: 10180 Comm: syz.6.1374 Tainted: G    B        L      syzkaller #0 PREEMPT 
Tainted: [B]=BAD_PAGE, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/02/2026
pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : copy_range_info_to_user fs/notify/fanotify/fanotify_user.c:682 [inline]
pc : copy_info_records_to_user fs/notify/fanotify/fanotify_user.c:813 [inline]
pc : copy_event_to_user fs/notify/fanotify/fanotify_user.c:944 [inline]
pc : fanotify_read+0x13d8/0x23a4 fs/notify/fanotify/fanotify_user.c:1032
lr : copy_range_info_to_user fs/notify/fanotify/fanotify_user.c:682 [inline]
lr : copy_info_records_to_user fs/notify/fanotify/fanotify_user.c:813 [inline]
lr : copy_event_to_user fs/notify/fanotify/fanotify_user.c:944 [inline]
lr : fanotify_read+0x13d8/0x23a4 fs/notify/fanotify/fanotify_user.c:1032
sp : ffff800092ca7740
x29: ffff800092ca79b0 x28: ffff0000d47fc8f0 x27: 0000000000000000
x26: ffff800092bb7b08 x25: dfff800000000000 x24: 1fffe00019037740
x23: ffff0000c81bba00 x22: ffff0000d50f9000 x21: 0000000020000300
x20: 00000000000000cb x19: 0000000020000300 x18: 1fffe00035beb820
x17: 0000000000000003 x16: ffff800088a0b000 x15: ffff800088abda60
x14: ffff0001adf5c10c x13: 0000000000000001 x12: 0000000000000000
x11: 0000000000000000 x10: 0000000000080000 x9 : 0000000000000000
x8 : ffff0000c81bba00 x7 : 0000000000000000 x6 : ffff80008048076c
x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff8000802f40a4
x2 : 0000000000000000 x1 : ffff0000c81bba00 x0 : 0000000000000001
Call trace:
 copy_range_info_to_user fs/notify/fanotify/fanotify_user.c:682 [inline] (P)
 copy_info_records_to_user fs/notify/fanotify/fanotify_user.c:813 [inline] (P)
 copy_event_to_user fs/notify/fanotify/fanotify_user.c:944 [inline] (P)
 fanotify_read+0x13d8/0x23a4 fs/notify/fanotify/fanotify_user.c:1032 (P)
 do_loop_readv_writev+0x24c/0x3dc fs/read_write.c:-1
 vfs_readv+0x258/0x520 fs/read_write.c:1022
 do_readv+0x134/0x2a8 fs/read_write.c:1082
 __do_sys_readv fs/read_write.c:1167 [inline]
 __se_sys_readv fs/read_write.c:1164 [inline]
 __arm64_sys_readv+0x80/0x94 fs/read_write.c:1164
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736
 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594
Code: 38796908 34000068 aa1a03e0 97f75966 (f9400348) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	38796908 	ldrb	w8, [x8, x25]
   4:	34000068 	cbz	w8, 0x10
   8:	aa1a03e0 	mov	x0, x26
   c:	97f75966 	bl	0xffffffffffdd65a4
* 10:	f9400348 	ldr	x8, [x26] <-- trapping instruction

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/23 12:22 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 92e3f6ef4ffb 4b1d8f01 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: vmalloc-out-of-bounds Read in fanotify_read
* Struck through repros no longer work on HEAD.