KASAN: use-after-free Read in sysv_new_inode

Status: upstream: reported C repro on 2024/04/14 13:45
Bug presence: origin:upstream
Labels: missing-backport
[Documentation on labels]
Reported-by: syzbot+3d6b2fd70949d09bcec7@syzkaller.appspotmail.com
First crash: 942d, last: 3d07h
Fix commit to backport (bisect log) :
tree: upstream
commit 00dac020ca2a2d82c3e4057a930794cca593ea77
Author: Eric Sandeen <sandeen@redhat.com>
Date: Wed Feb 5 22:30:09 2025 +0000

  sysv: convert sysv to use the new mount api

  
Fix bisection: the issue occurs on the latest tested release (bisect log)
Crash: KASAN: use-after-free Read in sysv_new_inode (log)
Repro: C syz .config
  
▶ ▼ Bug presence (3)
Date Name Commit Repro Result
2025/05/05 linux-5.15.y (ToT) 16fdf2c7111b C [report] KASAN: use-after-free Read in sysv_new_inode
2025/03/16 upstream (ToT) cb82ca153949 C [report] KASAN: use-after-free Read in sysv_new_inode
2025/05/05 upstream (ToT) 92a09c47464d C Didn't crash
▶ ▼ Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 KASAN: use-after-free Read in sysv_new_inode origin:upstream missing-backport 19 syz, C inconclusive 3429 3d21h 933d 0/3 upstream: reported C repro on 2024/04/22 17:59
linux-6.6 KASAN: use-after-free Read in sysv_new_inode origin:lts-only 19 syz, C inconclusive 137 136d 487d 0/2 upstream: reported C repro on 2025/07/13 15:52
upstream KASAN: use-after-free Read in sysv_new_inode fs 19 1 1011d 1007d 0/29 auto-obsoleted due to no activity on 2024/04/05 09:37
upstream KASAN: use-after-free Read in sysv_new_inode (2) fs 19 syz, C inconclusive error 21224 584d 917d 29/29 fixed on 2025/07/16 08:24
▶ ▼ Last patch testing requests (10)
Created Duration User Patch Repo Result
2026/09/30 13:11 18m retest repro linux-5.15.y report job log log
2026/09/30 13:11 20m retest repro linux-5.15.y report job log log
2026/09/06 06:03 18m retest repro linux-5.15.y report job log log
2026/09/06 06:03 13m retest repro linux-5.15.y report job log log
2026/09/06 06:03 24m retest repro linux-5.15.y report job log log
2026/09/06 06:03 13m retest repro linux-5.15.y report job log log
2026/09/06 06:03 18m retest repro linux-5.15.y report job log log
2026/08/21 00:09 16m retest repro linux-5.15.y report job log log
2026/08/21 00:09 19m retest repro linux-5.15.y report job log log
2026/07/10 07:08 16m retest repro linux-5.15.y report log
▶ ▼ Fix bisection attempts (2)
Created Duration User Patch Repo Result
2025/06/04 22:42 8h26m fix candidate upstream OK (1) job log
2024/08/31 22:55 1h57m bisect fix linux-5.15.y OK (0) job log log

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in sysv_new_inode+0x1105/0x1290 fs/sysv/ialloc.c:153
Read of size 2 at addr ffff88806a9d81ce by task syz.0.17/4375

CPU: 0 PID: 4375 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 sysv_new_inode+0x1105/0x1290 fs/sysv/ialloc.c:153
 sysv_mknod+0x4a/0xd0 fs/sysv/namei.c:53
 vfs_create+0x2db/0x460 fs/namei.c:3213
 do_mknodat+0x49e/0x630 fs/namei.c:4045
 __do_sys_mknodat fs/namei.c:4073 [inline]
 __se_sys_mknodat fs/namei.c:4070 [inline]
 __x64_sys_mknodat+0xa5/0xc0 fs/namei.c:4070
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f972198cb19
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffc7d8d368 EFLAGS: 00000246 ORIG_RAX: 0000000000000103
RAX: ffffffffffffffda RBX: 00007f9721c12fa0 RCX: 00007f972198cb19
RDX: 0000000000000008 RSI: 000020000000a5c0 RDI: 0000000000000004
RBP: 00007f9721a24b70 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9721c12fac R14: 00007f9721c12fa0 R15: 00007f9721c12fa0
 </TASK>

The buggy address belongs to the page:
page:ffffea0001aa7600 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x6a9d8
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001a92448 ffffea0001aae708 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Movable, gfp_mask 0x1100dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), pid 4375, ts 80018419349, free_ts 80261881415
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x24f6/0x2670 mm/page_alloc.c:4192
 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501
 alloc_pages_vma+0x2bc/0x790 mm/mempolicy.c:2146
 do_anonymous_page mm/memory.c:3838 [inline]
 handle_pte_fault mm/memory.c:4648 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x23be/0x4440 mm/memory.c:4883
 do_user_addr_fault+0x494/0xc90 arch/x86/mm/fault.c:1355
 handle_page_fault arch/x86/mm/fault.c:1443 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1496
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
 free_unref_page_list+0x119/0x830 mm/page_alloc.c:3433
 release_pages+0x185f/0x1bd0 mm/swap.c:963
 tlb_batch_pages_flush mm/mmu_gather.c:50 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:241 [inline]
 tlb_flush_mmu mm/mmu_gather.c:248 [inline]
 tlb_finish_mmu+0x1b4/0x370 mm/mmu_gather.c:371
 unmap_region+0x344/0x3b0 mm/mmap.c:2677
 __do_munmap+0xa29/0xe10 mm/mmap.c:2907
 __vm_munmap+0x13f/0x240 mm/mmap.c:2960
 __do_sys_munmap mm/mmap.c:2986 [inline]
 __se_sys_munmap mm/mmap.c:2982 [inline]
 __x64_sys_munmap+0x67/0x70 mm/mmap.c:2982
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
 ffff88806a9d8080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806a9d8100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88806a9d8180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff88806a9d8200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806a9d8280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

Crashes (3156):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/11/09 09:08 linux-5.15.y 29c6cdaac04a 5cecaf1f .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2 (corrupt fs)] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2025/12/27 23:47 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2025/12/11 08:16 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2025/09/01 23:15 linux-5.15.y 01879f56bdde 807a3b61 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2025/08/23 18:22 linux-5.15.y c79648372d02 bf27483f .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2025/05/13 12:43 linux-5.15.y 3b8db0e4f263 f6671af7 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2025/01/27 04:13 linux-5.15.y 003148680b79 9fbd772e .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2025/05/08 01:47 linux-5.15.y 16fdf2c7111b dbf35fa1 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan-arm64 KASAN: use-after-free Read in sysv_new_inode
2024/12/18 16:00 linux-5.15.y 963e654022cc a0626d3a .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan-arm64 KASAN: use-after-free Read in sysv_new_inode
2024/05/04 21:20 linux-5.15.y 284087d4f7d5 610f2a54 .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in sysv_new_inode
2026/11/09 08:04 linux-5.15.y 29c6cdaac04a 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/05/11 05:30 linux-5.15.y de8dfb3f0278 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/04/20 04:35 linux-5.15.y b9d57c40a767 303e2802 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/03/29 18:59 linux-5.15.y 91d48252ad4b b5ceaad2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/03/09 13:53 linux-5.15.y 91d48252ad4b 176bead5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/03/09 13:52 linux-5.15.y 91d48252ad4b 176bead5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/03/09 04:05 linux-5.15.y 91d48252ad4b 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/02/21 15:43 linux-5.15.y 3330a8d33e08 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/02/16 00:15 linux-5.15.y e45d5d41c134 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/02/15 18:34 linux-5.15.y e45d5d41c134 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/02/14 20:26 linux-5.15.y e45d5d41c134 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/02/14 19:59 linux-5.15.y e45d5d41c134 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/02/02 07:44 linux-5.15.y 9eec9a14ee10 6b8752f2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/18 20:35 linux-5.15.y 68efe5a6c16a 20d37d28 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/17 02:54 linux-5.15.y 68efe5a6c16a 20d37d28 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/17 01:48 linux-5.15.y 68efe5a6c16a 20d37d28 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/16 23:28 linux-5.15.y 68efe5a6c16a 20d37d28 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/16 12:19 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/16 06:17 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/15 20:50 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/15 03:18 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/14 16:52 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/13 09:57 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/13 02:36 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/12 20:42 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/12 18:04 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/12 13:27 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/12 01:14 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/11 21:42 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/11 11:14 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/11 07:50 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/10 20:18 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/09 21:40 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/08 17:59 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/08 16:32 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/08 15:22 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/08 05:40 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/07 17:55 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/06 04:24 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/05 20:04 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/05 06:41 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/05 05:17 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/04 18:30 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/04 13:22 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/04 04:26 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2026/01/03 21:50 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in sysv_new_inode
2025/08/26 17:23 linux-5.15.y c79648372d02 e12e5ba4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: use-after-free Read in sysv_new_inode
2024/04/14 13:44 linux-5.15.y fa3df276cd36 c8349e48 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: use-after-free Read in sysv_new_inode
2025/03/25 15:41 linux-5.15.y 0c935c049b5c 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in sysv_new_inode
2025/01/03 13:43 linux-5.15.y 91786f140358 d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: out-of-bounds Read in sysv_new_inode
* Struck through repros no longer work on HEAD.