================================================================== BUG: KASAN: use-after-free in strcmp+0x9b/0xb0 lib/string.c:346 Read of size 1 at addr ffff888076684c84 by task syz-executor.2/32696 CPU: 0 PID: 32696 Comm: syz-executor.2 Not tainted 5.17.0-rc5-syzkaller-00041-g73878e5eb1bd #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0x8d/0x336 mm/kasan/report.c:255 __kasan_report mm/kasan/report.c:442 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:459 strcmp+0x9b/0xb0 lib/string.c:346 replace_vma_anon_name mm/madvise.c:141 [inline] madvise_update_vma+0x4e6/0x7f0 mm/madvise.c:212 madvise_vma_behavior+0x116/0x1910 mm/madvise.c:1043 madvise_walk_vmas+0x1d5/0x2d0 mm/madvise.c:1207 do_madvise mm/madvise.c:1385 [inline] do_madvise+0x249/0x3c0 mm/madvise.c:1343 __do_sys_madvise mm/madvise.c:1398 [inline] __se_sys_madvise mm/madvise.c:1396 [inline] __x64_sys_madvise+0xa6/0x110 mm/madvise.c:1396 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f08373eb059 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f0835d60168 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 00007f08374fdf60 RCX: 00007f08373eb059 RDX: 0000000000000000 RSI: 0000000000004000 RDI: 0000000020ffc000 RBP: 00007f083744508d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0837a31b1f R14: 00007f0835d60300 R15: 0000000000022000 Allocated by task 32696: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:436 [inline] ____kasan_kmalloc mm/kasan/common.c:515 [inline] ____kasan_kmalloc mm/kasan/common.c:474 [inline] __kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:524 kmalloc include/linux/slab.h:586 [inline] anon_vma_name_alloc mm/madvise.c:75 [inline] replace_vma_anon_name mm/madvise.c:146 [inline] madvise_update_vma+0x546/0x7f0 mm/madvise.c:212 madvise_vma_anon_name+0x7c/0xc0 mm/madvise.c:1236 madvise_walk_vmas+0x1d5/0x2d0 mm/madvise.c:1207 madvise_set_anon_name+0xac/0xe0 mm/madvise.c:1269 prctl_set_vma kernel/sys.c:2313 [inline] __do_sys_prctl+0xeb5/0x12d0 kernel/sys.c:2602 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Freed by task 32696: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track+0x21/0x30 mm/kasan/common.c:45 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free+0x126/0x160 mm/kasan/common.c:328 kasan_slab_free include/linux/kasan.h:236 [inline] slab_free_hook mm/slub.c:1728 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1754 slab_free mm/slub.c:3509 [inline] kfree+0xd0/0x390 mm/slub.c:4562 vma_anon_name_free mm/madvise.c:88 [inline] kref_put include/linux/kref.h:65 [inline] free_vma_anon_name mm/madvise.c:125 [inline] free_vma_anon_name+0xeb/0x110 mm/madvise.c:116 vm_area_free+0x11/0x30 kernel/fork.c:376 __vma_adjust+0x836/0x24a0 mm/mmap.c:962 vma_merge+0x3fa/0xeb0 mm/mmap.c:1237 madvise_update_vma+0x1b6/0x7f0 mm/madvise.c:180 madvise_vma_behavior+0x116/0x1910 mm/madvise.c:1043 madvise_walk_vmas+0x1d5/0x2d0 mm/madvise.c:1207 do_madvise mm/madvise.c:1385 [inline] do_madvise+0x249/0x3c0 mm/madvise.c:1343 __do_sys_madvise mm/madvise.c:1398 [inline] __se_sys_madvise mm/madvise.c:1396 [inline] __x64_sys_madvise+0xa6/0x110 mm/madvise.c:1396 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae The buggy address belongs to the object at ffff888076684c80 which belongs to the cache kmalloc-16 of size 16 The buggy address is located 4 bytes inside of 16-byte region [ffff888076684c80, ffff888076684c90) The buggy address belongs to the page: page:ffffea0001d9a100 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888076684100 pfn:0x76684 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 0000000000000000 dead000000000001 ffff888010c413c0 raw: ffff888076684100 000000008080007f 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 3626, ts 134187830495, free_ts 134129445150 prep_new_page mm/page_alloc.c:2434 [inline] get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4165 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5389 __alloc_pages_node include/linux/gfp.h:572 [inline] alloc_slab_page mm/slub.c:1801 [inline] allocate_slab+0x80/0x3c0 mm/slub.c:1944 new_slab mm/slub.c:2004 [inline] ___slab_alloc+0xbe1/0x12b0 mm/slub.c:3018 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3105 slab_alloc_node mm/slub.c:3196 [inline] __kmalloc_node+0x339/0x4a0 mm/slub.c:4468 kmalloc_node include/linux/slab.h:604 [inline] kvmalloc_node+0x3e/0x100 mm/util.c:580 xt_jumpstack_alloc net/netfilter/x_tables.c:1354 [inline] xt_replace_table+0x1a2/0x820 net/netfilter/x_tables.c:1393 __do_replace+0x1d7/0x890 net/ipv6/netfilter/ip6_tables.c:1084 do_replace net/ipv6/netfilter/ip6_tables.c:1157 [inline] do_ip6t_set_ctl+0x90d/0xb90 net/ipv6/netfilter/ip6_tables.c:1639 nf_setsockopt+0x83/0xe0 net/netfilter/nf_sockopt.c:101 ipv6_setsockopt+0x122/0x180 net/ipv6/ipv6_sockglue.c:1024 tcp_setsockopt+0x136/0x2520 net/ipv4/tcp.c:3694 __sys_setsockopt+0x2db/0x610 net/socket.c:2180 __do_sys_setsockopt net/socket.c:2191 [inline] __se_sys_setsockopt net/socket.c:2188 [inline] __x64_sys_setsockopt+0xba/0x150 net/socket.c:2188 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1352 [inline] free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1404 free_unref_page_prepare mm/page_alloc.c:3325 [inline] free_unref_page_list+0x1a9/0xfa0 mm/page_alloc.c:3441 release_pages+0x317/0x1220 mm/swap.c:980 tlb_batch_pages_flush mm/mmu_gather.c:50 [inline] tlb_flush_mmu_free mm/mmu_gather.c:243 [inline] tlb_flush_mmu mm/mmu_gather.c:250 [inline] tlb_finish_mmu+0x165/0x8c0 mm/mmu_gather.c:341 exit_mmap+0x21b/0x670 mm/mmap.c:3180 __mmput+0x122/0x4b0 kernel/fork.c:1114 mmput+0x56/0x60 kernel/fork.c:1135 exit_mm kernel/exit.c:507 [inline] do_exit+0xa3c/0x2a30 kernel/exit.c:793 do_group_exit+0xd2/0x2f0 kernel/exit.c:935 get_signal+0x45a/0x2490 kernel/signal.c:2863 arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:868 handle_signal_work kernel/entry/common.c:148 [inline] exit_to_user_mode_loop kernel/entry/common.c:172 [inline] exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:207 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae Memory state around the buggy address: ffff888076684b80: 00 00 fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc ffff888076684c00: 00 00 fc fc 00 00 fc fc fa fb fc fc 00 00 fc fc >ffff888076684c80: fa fb fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc ^ ffff888076684d00: 00 00 fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc ffff888076684d80: 00 00 fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc ==================================================================