syzbot

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BUG: KASAN: use-after-free in dev_map_generic_redirect+0xa0/0x650 kernel/bpf/devmap.c:668
Read of size 8 at addr ffff88805859e480 by task syz.9.1007/8701

CPU: 1 PID: 8701 Comm: syz.9.1007 Not tainted 6.1.128-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
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:316 [inline]
 print_report+0x15f/0x4f0 mm/kasan/report.c:427
 kasan_report+0x136/0x160 mm/kasan/report.c:531
 dev_map_generic_redirect+0xa0/0x650 kernel/bpf/devmap.c:668
 xdp_do_generic_redirect_map net/core/filter.c:4416 [inline]
 xdp_do_generic_redirect+0x4bf/0x850 net/core/filter.c:4475
 do_xdp_generic+0x50b/0x6d0 net/core/dev.c:4957
 tun_get_user+0x261e/0x42d0 drivers/net/tun.c:1920
 tun_chr_write_iter+0x10c/0x1f0 drivers/net/tun.c:2044
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x857/0xbc0 fs/read_write.c:584
 ksys_write+0x19c/0x2c0 fs/read_write.c:637
 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: 0033:0x7fe1c318b85f
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48
RSP: 002b:00007fe1c40a3000 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fe1c33a5fa0 RCX: 00007fe1c318b85f
RDX: 000000000000fe53 RSI: 0000000020000440 RDI: 00000000000000c8
RBP: 00007fe1c320e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000fe53 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fe1c33a5fa0 R15: 00007ffeeda04c18
 </TASK>

Allocated by task 7678:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 __kasan_kmalloc+0x97/0xb0 mm/kasan/common.c:383
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __do_kmalloc_node mm/slab_common.c:936 [inline]
 __kmalloc_node+0xb3/0x230 mm/slab_common.c:943
 kmalloc_node include/linux/slab.h:589 [inline]
 kvmalloc_node+0x6e/0x180 mm/util.c:581
 kvmalloc include/linux/slab.h:716 [inline]
 alloc_fdtable+0x154/0x280 fs/file.c:138
 dup_fd+0x95c/0xca0 fs/file.c:337
 copy_files+0x72/0xe0 kernel/fork.c:1636
 copy_process+0x1873/0x4060 kernel/fork.c:2254
 kernel_clone+0x222/0x920 kernel/fork.c:2681
 __do_sys_clone kernel/fork.c:2822 [inline]
 __se_sys_clone kernel/fork.c:2806 [inline]
 __x64_sys_clone+0x231/0x280 kernel/fork.c:2806
 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

The buggy address belongs to the object at ffff88805859e480
 which belongs to the cache kmalloc-cg-96 of size 96
The buggy address is located 0 bytes inside of
 96-byte region [ffff88805859e480, ffff88805859e4e0)

The buggy address belongs to the physical page:
page:ffffea0001616780 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88805859ea00 pfn:0x5859e
memcg:ffff88807881f601
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea0004ff9900 dead000000000002 ffff888017c428c0
raw: ffff88805859ea00 0000000080200005 00000001ffffffff ffff88807881f601
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 4432, tgid 4432 (syz.1.39), ts 70375517441, free_ts 70343796593
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x18d/0x1b0 mm/page_alloc.c:2532
 prep_new_page mm/page_alloc.c:2539 [inline]
 get_page_from_freelist+0x3731/0x38d0 mm/page_alloc.c:4328
 __alloc_pages+0x28d/0x770 mm/page_alloc.c:5605
 alloc_slab_page+0x6a/0x150 mm/slub.c:1794
 allocate_slab mm/slub.c:1939 [inline]
 new_slab+0x84/0x2d0 mm/slub.c:1992
 ___slab_alloc+0xc20/0x1270 mm/slub.c:3180
 __slab_alloc mm/slub.c:3279 [inline]
 slab_alloc_node mm/slub.c:3364 [inline]
 __kmem_cache_alloc_node+0x19f/0x260 mm/slub.c:3437
 kmalloc_trace+0x26/0xe0 mm/slab_common.c:1026
 kmalloc include/linux/slab.h:563 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 get_undo_list ipc/sem.c:1856 [inline]
 copy_semundo+0xb1/0x230 ipc/sem.c:2314
 copy_process+0x1848/0x4060 kernel/fork.c:2251
 kernel_clone+0x222/0x920 kernel/fork.c:2681
 __do_sys_clone3 kernel/fork.c:2980 [inline]
 __se_sys_clone3+0x373/0x410 kernel/fork.c:2964
 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
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1459 [inline]
 free_pcp_prepare mm/page_alloc.c:1509 [inline]
 free_unref_page_prepare+0x12a6/0x15b0 mm/page_alloc.c:3384
 free_unref_page_list+0x663/0x900 mm/page_alloc.c:3525
 release_pages+0x24c4/0x27a0 mm/swap.c:1035
 tlb_batch_pages_flush mm/mmu_gather.c:59 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:254 [inline]
 tlb_flush_mmu+0xfc/0x210 mm/mmu_gather.c:261
 tlb_finish_mmu+0xce/0x1f0 mm/mmu_gather.c:361
 exit_mmap+0x3b3/0x980 mm/mmap.c:3250
 __mmput+0x115/0x3c0 kernel/fork.c:1200
 exit_mm+0x226/0x300 kernel/exit.c:565
 do_exit+0x9f1/0x26a0 kernel/exit.c:858
 do_group_exit+0x202/0x2b0 kernel/exit.c:1021
 get_signal+0x16f7/0x17d0 kernel/signal.c:2871
 arch_do_signal_or_restart+0xb0/0x1a10 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87

Memory state around the buggy address:
 ffff88805859e380: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
 ffff88805859e400: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
>ffff88805859e480: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
                   ^
 ffff88805859e500: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff88805859e580: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
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