syzbot

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BUG: KASAN: use-after-free in next_signal+0xa7/0xc0 kernel/signal.c:219
Read of size 8 at addr ffff888075944938 by task syz-executor.0/14952

CPU: 0 PID: 14952 Comm: syz-executor.0 Not tainted 6.2.0-rc3-next-20230112-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:306 [inline]
 print_report+0x15e/0x45d mm/kasan/report.c:417
 kasan_report+0xc0/0xf0 mm/kasan/report.c:517
 next_signal+0xa7/0xc0 kernel/signal.c:219
 signalfd_poll+0x119/0x200 fs/signalfd.c:59
 vfs_poll include/linux/poll.h:88 [inline]
 io_poll_check_events io_uring/poll.c:279 [inline]
 io_poll_task_func+0x3a6/0x1220 io_uring/poll.c:327
 handle_tw_list+0xa8/0x460 io_uring/io_uring.c:1169
 tctx_task_work+0x12e/0x530 io_uring/io_uring.c:1224
 task_work_run+0x16f/0x270 kernel/task_work.c:179
 get_signal+0x1c7/0x24f0 kernel/signal.c:2635
 arch_do_signal_or_restart+0x79/0x5c0 arch/x86/kernel/signal.c:306
 exit_to_user_mode_loop kernel/entry/common.c:168 [inline]
 exit_to_user_mode_prepare+0x11f/0x240 kernel/entry/common.c:204
 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
 syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:297
 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fa230a8c0c9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa2317a7168 EFLAGS: 00000246 ORIG_RAX: 0000000000000029
RAX: 0000000000000006 RBX: 00007fa230babf80 RCX: 00007fa230a8c0c9
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001
RBP: 00007fa230ae7ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe9c1a119f R14: 00007fa2317a7300 R15: 0000000000022000
 </TASK>

Allocated by task 14952:
 kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:371 [inline]
 ____kasan_kmalloc mm/kasan/common.c:330 [inline]
 __kasan_kmalloc+0xa2/0xb0 mm/kasan/common.c:380
 kmalloc include/linux/slab.h:580 [inline]
 do_signalfd4+0x261/0x3c0 fs/signalfd.c:268
 __do_sys_signalfd4 fs/signalfd.c:311 [inline]
 __se_sys_signalfd4 fs/signalfd.c:302 [inline]
 __x64_sys_signalfd4+0x13c/0x1c0 fs/signalfd.c:302
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 14952:
 kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 kasan_save_free_info+0x2e/0x40 mm/kasan/generic.c:518
 ____kasan_slab_free mm/kasan/common.c:236 [inline]
 ____kasan_slab_free+0x160/0x1c0 mm/kasan/common.c:200
 kasan_slab_free include/linux/kasan.h:162 [inline]
 slab_free_hook mm/slub.c:1781 [inline]
 slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1807
 slab_free mm/slub.c:3787 [inline]
 __kmem_cache_free+0xaf/0x2d0 mm/slub.c:3800
 signalfd_release+0x37/0x50 fs/signalfd.c:47
 __fput+0x27c/0xa90 fs/file_table.c:321
 task_work_run+0x16f/0x270 kernel/task_work.c:179
 get_signal+0x1c7/0x24f0 kernel/signal.c:2635
 arch_do_signal_or_restart+0x79/0x5c0 arch/x86/kernel/signal.c:306
 exit_to_user_mode_loop kernel/entry/common.c:168 [inline]
 exit_to_user_mode_prepare+0x11f/0x240 kernel/entry/common.c:204
 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
 syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:297
 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff888075944938
 which belongs to the cache kmalloc-8 of size 8
The buggy address is located 0 bytes inside of
 8-byte region [ffff888075944938, ffff888075944940)

The buggy address belongs to the physical page:
page:ffffea0001d65100 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x75944
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffff888012441280 dead000000000100 dead000000000122
raw: 0000000000000000 0000000080660066 00000001ffffffff 0000000000000000
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 5111, tgid 5111 (syz-executor.2), ts 653688312166, free_ts 653668447728
 prep_new_page mm/page_alloc.c:2549 [inline]
 get_page_from_freelist+0x11bb/0x2d50 mm/page_alloc.c:4324
 __alloc_pages+0x1cb/0x5c0 mm/page_alloc.c:5590
 alloc_pages+0x1aa/0x270 mm/mempolicy.c:2281
 alloc_slab_page mm/slub.c:1851 [inline]
 allocate_slab+0x25f/0x350 mm/slub.c:1998
 new_slab mm/slub.c:2051 [inline]
 ___slab_alloc+0xa91/0x1400 mm/slub.c:3193
 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3292
 __slab_alloc_node mm/slub.c:3345 [inline]
 slab_alloc_node mm/slub.c:3442 [inline]
 __kmem_cache_alloc_node+0x136/0x330 mm/slub.c:3491
 __do_kmalloc_node mm/slab_common.c:966 [inline]
 __kmalloc_node+0x4d/0xd0 mm/slab_common.c:974
 kmalloc_node include/linux/slab.h:610 [inline]
 __vmalloc_area_node mm/vmalloc.c:3062 [inline]
 __vmalloc_node_range+0xc0b/0x12e0 mm/vmalloc.c:3246
 __vmalloc_node mm/vmalloc.c:3311 [inline]
 vzalloc+0x6b/0x80 mm/vmalloc.c:3384
 xt_counters_alloc+0x50/0x70 net/netfilter/x_tables.c:1379
 __do_replace+0x9a/0x900 net/ipv4/netfilter/arp_tables.c:894
 do_replace net/ipv6/netfilter/ip6_tables.c:1157 [inline]
 do_ip6t_set_ctl+0x8a9/0xb30 net/ipv6/netfilter/ip6_tables.c:1639
 nf_setsockopt+0x87/0xe0 net/netfilter/nf_sockopt.c:101
 ipv6_setsockopt+0x12b/0x190 net/ipv6/ipv6_sockglue.c:1028
 tcp_setsockopt+0x9f/0x100 net/ipv4/tcp.c:3802
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1451 [inline]
 free_pcp_prepare+0x4d0/0x910 mm/page_alloc.c:1501
 free_unref_page_prepare mm/page_alloc.c:3387 [inline]
 free_unref_page+0x1d/0x490 mm/page_alloc.c:3482
 __folio_put_small mm/swap.c:106 [inline]
 __folio_put+0xc5/0x140 mm/swap.c:129
 folio_put include/linux/mm.h:1203 [inline]
 put_page include/linux/mm.h:1272 [inline]
 generic_pipe_buf_release+0x23d/0x2b0 fs/pipe.c:210
 pipe_buf_release include/linux/pipe_fs_i.h:183 [inline]
 iov_iter_revert.part.0+0x402/0x730 lib/iov_iter.c:935
 iov_iter_revert+0x4c/0x60 lib/iov_iter.c:919
 __iomap_dio_rw+0x1677/0x1cf0 fs/iomap/direct-io.c:617
 iomap_dio_rw+0x40/0xa0 fs/iomap/direct-io.c:689
 ext4_dio_read_iter fs/ext4/file.c:94 [inline]
 ext4_file_read_iter+0x4be/0x690 fs/ext4/file.c:145
 call_read_iter include/linux/fs.h:1846 [inline]
 generic_file_splice_read+0x182/0x4b0 fs/splice.c:309
 do_splice_to+0x1b9/0x240 fs/splice.c:793
 splice_direct_to_actor+0x2ab/0x8a0 fs/splice.c:865
 do_splice_direct+0x1ab/0x280 fs/splice.c:974
 do_sendfile+0xb19/0x12c0 fs/read_write.c:1255
 __do_sys_sendfile64 fs/read_write.c:1323 [inline]
 __se_sys_sendfile64 fs/read_write.c:1309 [inline]
 __x64_sys_sendfile64+0x1d0/0x210 fs/read_write.c:1309
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80

Memory state around the buggy address:
 ffff888075944800: fc fc fc fc 05 fc fc fc fc fb fc fc fc fc fb fc
 ffff888075944880: fc fc fc fb fc fc fc fc 05 fc fc fc fc 05 fc fc
>ffff888075944900: fc fc fb fc fc fc fc fa fc fc fc fc fb fc fc fc
                                        ^
 ffff888075944980: fc fb fc fc fc fc 05 fc fc fc fc 05 fc fc fc fc
 ffff888075944a00: 05 fc fc fc fc 05 fc fc fc fc 05 fc fc fc fc 05
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