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KASAN: use-after-free Read in ocfs2_fault

Status: auto-obsoleted due to no activity on 2025/08/18 07:54
Reported-by: syzbot+af8c6eb5765c3ac0de6e@syzkaller.appspotmail.com
First crash: 309d, last: 309d
▶ ▼ 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 ocfs2_fault origin:lts-only 19 C error 20 58d 288d 0/3 upstream: reported C repro on 2025/05/31 00:13
linux-5.15 KASAN: use-after-free Read in ocfs2_fault (2) origin:upstream 19 C error 2 45d 59d 0/3 upstream: reported C repro on 2026/01/15 08:30
upstream KASAN: slab-use-after-free Read in ocfs2_fault ocfs2 19 C done 346 19h50m 549d 0/29 upstream: reported C repro on 2024/09/12 09:21
linux-6.6 KASAN: slab-use-after-free Read in ocfs2_fault origin:upstream missing-backport 19 C error 3 81d 179d 0/2 upstream: reported C repro on 2025/09/17 19:37

Sample crash report:
netlink: 'syz.4.275': attribute type 2 has an invalid length.
netlink: 'syz.4.275': attribute type 2 has an invalid length.
==================================================================
BUG: KASAN: use-after-free in ocfs2_fault+0xc8/0x414 fs/ocfs2/mmap.c:41
Read of size 8 at addr ffff0000c1da03b8 by task syz.4.275/5117

CPU: 0 PID: 5117 Comm: syz.4.275 Not tainted 5.15.182-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
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
 print_address_description+0x78/0x30c mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xec/0x15c mm/kasan/report.c:451
 __asan_report_load8_noabort+0x44/0x50 mm/kasan/report_generic.c:309
 ocfs2_fault+0xc8/0x414 fs/ocfs2/mmap.c:41
 __do_fault+0x120/0x5d0 mm/memory.c:3928
 do_read_fault mm/memory.c:4264 [inline]
 do_fault mm/memory.c:4392 [inline]
 handle_pte_fault mm/memory.c:4650 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x1b4c/0x2950 mm/memory.c:4883
 __do_page_fault arch/arm64/mm/fault.c:505 [inline]
 do_page_fault+0x694/0xad4 arch/arm64/mm/fault.c:605
 do_translation_fault+0xe0/0x130 arch/arm64/mm/fault.c:686
 do_mem_abort+0x6c/0x1ac arch/arm64/mm/fault.c:819
 el1_abort+0x3c/0x5c arch/arm64/kernel/entry-common.c:358
 el1h_64_sync_handler+0x80/0xcc arch/arm64/kernel/entry-common.c:418
 el1h_64_sync+0x78/0x7c arch/arm64/kernel/entry.S:522
 __arch_copy_from_user+0x84/0x218 arch/arm64/lib/copy_template.S:89
 copy_msghdr_from_user net/socket.c:2369 [inline]
 sendmsg_copy_msghdr net/socket.c:2467 [inline]
 ___sys_sendmsg+0x140/0x240 net/socket.c:2486
 __sys_sendmsg net/socket.c:2519 [inline]
 __do_sys_sendmsg net/socket.c:2528 [inline]
 __se_sys_sendmsg net/socket.c:2526 [inline]
 __arm64_sys_sendmsg+0x1a8/0x254 net/socket.c:2526
 __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

Allocated by task 5154:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 __kasan_slab_alloc+0x8c/0xcc mm/kasan/common.c:467
 kasan_slab_alloc include/linux/kasan.h:254 [inline]
 slab_post_alloc_hook+0x74/0x408 mm/slab.h:519
 slab_alloc_node mm/slub.c:3220 [inline]
 slab_alloc mm/slub.c:3228 [inline]
 kmem_cache_alloc+0x1e0/0x3e4 mm/slub.c:3233
 vm_area_alloc+0x2c/0xe0 kernel/fork.c:350
 __mmap_region mm/mmap.c:1770 [inline]
 mmap_region+0x99c/0x1390 mm/mmap.c:2921
 do_mmap+0x67c/0xdb4 mm/mmap.c:1574
 vm_mmap_pgoff+0x184/0x284 mm/util.c:551
 ksys_mmap_pgoff+0x410/0x620 mm/mmap.c:1623
 __do_sys_mmap arch/arm64/kernel/sys.c:28 [inline]
 __se_sys_mmap arch/arm64/kernel/sys.c:21 [inline]
 __arm64_sys_mmap+0xf8/0x110 arch/arm64/kernel/sys.c:21
 __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

Freed by task 5154:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4c/0x84 mm/kasan/common.c:46
 kasan_set_free_info+0x28/0x4c mm/kasan/generic.c:360
 ____kasan_slab_free+0x118/0x164 mm/kasan/common.c:366
 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:374
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1705 [inline]
 slab_free_freelist_hook+0x128/0x1e8 mm/slub.c:1731
 slab_free mm/slub.c:3499 [inline]
 kmem_cache_free+0xdc/0x3b4 mm/slub.c:3515
 vm_area_free+0x28/0x38 kernel/fork.c:376
 remove_vma mm/mmap.c:187 [inline]
 remove_vma_list mm/mmap.c:2616 [inline]
 __do_munmap+0xaa0/0xc04 mm/mmap.c:2890
 do_munmap mm/mmap.c:2898 [inline]
 munmap_vma_range mm/mmap.c:602 [inline]
 __mmap_region mm/mmap.c:1745 [inline]
 mmap_region+0x7b0/0x1390 mm/mmap.c:2921
 do_mmap+0x67c/0xdb4 mm/mmap.c:1574
 vm_mmap_pgoff+0x184/0x284 mm/util.c:551
 ksys_mmap_pgoff+0x410/0x620 mm/mmap.c:1623
 __do_sys_mmap arch/arm64/kernel/sys.c:28 [inline]
 __se_sys_mmap arch/arm64/kernel/sys.c:21 [inline]
 __arm64_sys_mmap+0xf8/0x110 arch/arm64/kernel/sys.c:21
 __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

The buggy address belongs to the object at ffff0000c1da0318
 which belongs to the cache vm_area_struct of size 200
The buggy address is located 160 bytes inside of
 200-byte region [ffff0000c1da0318, ffff0000c1da03e0)
The buggy address belongs to the page:
page:000000005e52425c refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x101da0
memcg:ffff0000c9b4fe01
flags: 0x5ffc00000000200(slab|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000200 0000000000000000 0000000900000001 ffff0000c0841500
raw: 0000000000000000 00000000000f000f 00000001ffffffff ffff0000c9b4fe01
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000c1da0280: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc
 ffff0000c1da0300: fc fc fc fa fb fb fb fb fb fb fb fb fb fb fb fb
>ffff0000c1da0380: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
                                        ^
 ffff0000c1da0400: fc fc fc fc fa fb fb fb fb fb fb fb fb fb fb fb
 ffff0000c1da0480: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/10 07:54 linux-5.15.y 3b8db0e4f263 77908e5f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: use-after-free Read in ocfs2_fault
* Struck through repros no longer work on HEAD.