==================================================================
BUG: KASAN: use-after-free in user_mode arch/x86/include/asm/ptrace.h:131 [inline]
BUG: KASAN: use-after-free in trace_page_fault_entries arch/x86/mm/fault.c:1516 [inline]
BUG: KASAN: use-after-free in do_page_fault+0x6d/0x360 arch/x86/mm/fault.c:1528
Read of size 8 at addr ffff8881d0f8ff20 by task syz.4.257/1264

CPU: 0 PID: 1264 Comm: syz.4.257 Not tainted 5.4.290-syzkaller-00001-g986c38813dff #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:

The buggy address belongs to the page:
page:ffffea000743e3c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x8000000000000000()
raw: 8000000000000000 0000000000000000 ffffea000743e388 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL)
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook mm/page_alloc.c:2165 [inline]
 prep_new_page+0x192/0x370 mm/page_alloc.c:2171
 get_page_from_freelist+0x2d13/0x2d90 mm/page_alloc.c:3794
 __alloc_pages_nodemask+0x393/0x840 mm/page_alloc.c:4893
 alloc_slab_page+0x3b/0x400 mm/slub.c:343
 allocate_slab mm/slub.c:1683 [inline]
 new_slab+0x98/0x430 mm/slub.c:1749
 new_slab_objects mm/slub.c:2505 [inline]
 ___slab_alloc+0x2e0/0x460 mm/slub.c:2667
 __slab_alloc+0x63/0xa0 mm/slub.c:2707
 slab_alloc_node mm/slub.c:2792 [inline]
 slab_alloc mm/slub.c:2837 [inline]
 kmem_cache_alloc+0x12a/0x260 mm/slub.c:2842
 getname_flags+0xba/0x520 fs/namei.c:141
 getname fs/namei.c:212 [inline]
 user_path_mountpoint_at+0x28/0x50 fs/namei.c:2842
 ksys_umount+0x143/0x410 fs/namespace.c:1690
 __do_sys_umount fs/namespace.c:1716 [inline]
 __se_sys_umount fs/namespace.c:1714 [inline]
 __x64_sys_umount+0x5a/0x70 fs/namespace.c:1714
 do_syscall_64+0xd8/0x170 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1176 [inline]
 __free_pages_ok+0x847/0x950 mm/page_alloc.c:1438
 free_the_page mm/page_alloc.c:4955 [inline]
 __free_pages+0x91/0x140 mm/page_alloc.c:4961
 __free_slab+0x21d/0x2d0 mm/slub.c:1774
 free_slab mm/slub.c:1789 [inline]
 discard_slab mm/slub.c:1795 [inline]
 unfreeze_partials+0x162/0x190 mm/slub.c:2288
 put_cpu_partial+0xbf/0x180 mm/slub.c:2324
 __slab_free+0x2a5/0x370 mm/slub.c:2971
 do_slab_free mm/slub.c:3068 [inline]
 ___cache_free+0xc1/0xd0 mm/slub.c:3087
 qlink_free+0x23/0x30 mm/kasan/quarantine.c:148
 qlist_free_all+0x47/0xb0 mm/kasan/quarantine.c:167
 quarantine_reduce+0x1e4/0x230 mm/kasan/quarantine.c:260
 __kasan_kmalloc+0x41/0x210 mm/kasan/common.c:507
 kasan_slab_alloc+0xe/0x10 mm/kasan/common.c:537
 slab_post_alloc_hook mm/slab.h:584 [inline]
 slab_alloc_node mm/slub.c:2829 [inline]
 slab_alloc mm/slub.c:2837 [inline]
 kmem_cache_alloc+0xe0/0x260 mm/slub.c:2842
 getname_flags+0xba/0x520 fs/namei.c:141
 getname+0x19/0x20 fs/namei.c:212
 do_sys_open+0x357/0x810 fs/open.c:1117

Memory state around the buggy address:
 ffff8881d0f8fe00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881d0f8fe80: 00 00 00 00 00 00 00 00 ff ff ff ff ff ff ff ff
>ffff8881d0f8ff00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                               ^
 ffff8881d0f8ff80: f1 f1 f1 f1 00 f2 f2 f2 04 f3 f3 f3 ff ff ff ff
 ffff8881d0f90000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
PANIC: double fault, error_code: 0x0
CPU: 0 PID: 1264 Comm: syz.4.257 Tainted: G    B             5.4.290-syzkaller-00001-g986c38813dff #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:perf_trace_x86_exceptions+0x18/0x410 arch/x86/include/asm/trace/exceptions.h:14
Code: 2e c5 0a 00 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 81 ec c0 00 00 00 <48> 89 4c 24 30 48 89 54 24 28 48 89 74 24 18 48 89 7c 24 08 65 48
RSP: 0018:ffff8881d0e46f40 EFLAGS: 00010082
RAX: ffff8881eca4c210 RBX: ffff8881d0e47098 RCX: 0000000000000000
RDX: ffff8881d0e47098 RSI: ffffe8ffffc3d1b0 RDI: ffffffff860b6620
RBP: ffff8881d0e47040 R08: ffffffff8130e85d R09: fffffbfff0cd8926
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff8881eca4c210
R13: dffffc0000000000 R14: ffffe8ffffc3d1b0 R15: 0000000000000000
FS:  00007f29517e56c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff8881d0e46f38 CR3: 00000001f5c2a000 CR4: 00000000003406b0
DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 <#DF>
 </#DF>
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	0a 00                	or     (%rax),%al
   2:	66 66 2e 0f 1f 84 00 	data16 cs nopw 0x0(%rax,%rax,1)
   9:	00 00 00 00
   d:	0f 1f 00             	nopl   (%rax)
  10:	55                   	push   %rbp
  11:	48 89 e5             	mov    %rsp,%rbp
  14:	41 57                	push   %r15
  16:	41 56                	push   %r14
  18:	41 55                	push   %r13
  1a:	41 54                	push   %r12
  1c:	53                   	push   %rbx
  1d:	48 83 e4 e0          	and    $0xffffffffffffffe0,%rsp
  21:	48 81 ec c0 00 00 00 	sub    $0xc0,%rsp
* 28:	48 89 4c 24 30       	mov    %rcx,0x30(%rsp) <-- trapping instruction
  2d:	48 89 54 24 28       	mov    %rdx,0x28(%rsp)
  32:	48 89 74 24 18       	mov    %rsi,0x18(%rsp)
  37:	48 89 7c 24 08       	mov    %rdi,0x8(%rsp)
  3c:	65                   	gs
  3d:	48                   	rex.W