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BUG: KASAN: use-after-free in bq_enqueue kernel/bpf/cpumap.c:751 [inline]
BUG: KASAN: use-after-free in cpu_map_enqueue+0x2dd/0x370 kernel/bpf/cpumap.c:775
Read of size 4 at addr ffff888043f9b078 by task syz.1.3164/18677

CPU: 0 PID: 18677 Comm: syz.1.3164 Not tainted 6.1.119-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:284 [inline]
 print_report+0x15f/0x4f0 mm/kasan/report.c:395
 kasan_report+0x136/0x160 mm/kasan/report.c:495
 bq_enqueue kernel/bpf/cpumap.c:751 [inline]
 cpu_map_enqueue+0x2dd/0x370 kernel/bpf/cpumap.c:775
 __xdp_do_redirect_frame net/core/filter.c:4300 [inline]
 xdp_do_redirect_frame+0x2f0/0x660 net/core/filter.c:4358
 xdp_test_run_batch net/bpf/test_run.c:314 [inline]
 bpf_test_run_xdp_live+0xbf4/0x1ea0 net/bpf/test_run.c:362
 bpf_prog_test_run_xdp+0x7d1/0x1130 net/bpf/test_run.c:1393
 bpf_prog_test_run+0x32f/0x3a0 kernel/bpf/syscall.c:3685
 __sys_bpf+0x3eb/0x6c0 kernel/bpf/syscall.c:5038
 __do_sys_bpf kernel/bpf/syscall.c:5124 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5122 [inline]
 __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:5122
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fea3bb7ff19
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fea3c944058 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007fea3bd45fa0 RCX: 00007fea3bb7ff19
RDX: 0000000000000050 RSI: 0000000020000240 RDI: 000000000000000a
RBP: 00007fea3bbf3986 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fea3bd45fa0 R15: 00007ffd612f01c8
 </TASK>

The buggy address belongs to the physical page:
page:ffffea00010fe6c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x43f9b
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 dead000000000100 dead000000000122 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 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 18279, tgid 18279 (syz.7.3065), ts 1798394852943, free_ts 1800147273147
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x18d/0x1b0 mm/page_alloc.c:2517
 prep_new_page mm/page_alloc.c:2524 [inline]
 get_page_from_freelist+0x3731/0x38d0 mm/page_alloc.c:4313
 __alloc_pages+0x28d/0x770 mm/page_alloc.c:5590
 __folio_alloc+0xf/0x30 mm/page_alloc.c:5622
 vma_alloc_folio+0x486/0x990 mm/mempolicy.c:2243
 shmem_alloc_folio mm/shmem.c:1589 [inline]
 shmem_alloc_and_acct_folio+0x5a8/0xd50 mm/shmem.c:1613
 shmem_get_folio_gfp+0x13f0/0x3470 mm/shmem.c:1941
 shmem_get_folio mm/shmem.c:2072 [inline]
 shmem_write_begin+0x16e/0x4e0 mm/shmem.c:2556
 generic_perform_write+0x2fc/0x5e0 mm/filemap.c:3845
 __generic_file_write_iter+0x176/0x400 mm/filemap.c:3973
 generic_file_write_iter+0xab/0x310 mm/filemap.c:4005
 __kernel_write_iter+0x2ff/0x710 fs/read_write.c:517
 dump_emit_page fs/coredump.c:881 [inline]
 dump_user_range+0x43d/0x8e0 fs/coredump.c:908
 elf_core_dump+0x3d2b/0x4590 fs/binfmt_elf.c:2313
 do_coredump+0x18b7/0x2700 fs/coredump.c:755
 get_signal+0x1454/0x17d0 kernel/signal.c:2857
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1444 [inline]
 free_pcp_prepare mm/page_alloc.c:1494 [inline]
 free_unref_page_prepare+0xf63/0x1120 mm/page_alloc.c:3369
 free_unref_page_list+0x663/0x900 mm/page_alloc.c:3510
 release_pages+0x2836/0x2b40 mm/swap.c:1055
 __pagevec_release+0x80/0xf0 mm/swap.c:1075
 pagevec_release include/linux/pagevec.h:71 [inline]
 folio_batch_release include/linux/pagevec.h:135 [inline]
 shmem_undo_range+0x865/0x2390 mm/shmem.c:946
 shmem_truncate_range mm/shmem.c:1062 [inline]
 shmem_evict_inode+0x265/0xa60 mm/shmem.c:1171
 evict+0x529/0x930 fs/inode.c:701
 do_unlinkat+0x509/0x820 fs/namei.c:4397
 __do_sys_unlink fs/namei.c:4438 [inline]
 __se_sys_unlink fs/namei.c:4436 [inline]
 __x64_sys_unlink+0x45/0x50 fs/namei.c:4436
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff888043f9af00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888043f9af80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888043f9b000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                                ^
 ffff888043f9b080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888043f9b100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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