================================================================== BUG: KASAN: use-after-free in strcmp+0x9b/0xb0 lib/string.c:346 Read of size 1 at addr ffff888075796f04 by task syz-executor.4/20278 CPU: 1 PID: 20278 Comm: syz-executor.4 Not tainted 5.17.0-rc2-next-20220204-syzkaller #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+0xa5/0x3e0 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+0x116/0x19d0 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: 0033:0x7f692e991059 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:00007f692d906168 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 00007f692eaa3f60 RCX: 00007f692e991059 RDX: 000000000000000b RSI: 0000000000001000 RDI: 0000000020ffc000 RBP: 00007f692e9eb08d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc2c67a9cf R14: 00007f692d906300 R15: 0000000000022000 Allocated by task 20278: 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:2305 [inline] __do_sys_prctl+0xeb5/0x12d0 kernel/sys.c:2594 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 20278: 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+0x166/0x1a0 mm/kasan/common.c:328 kasan_slab_free include/linux/kasan.h:226 [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+0xce/0x2d0 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:377 __vma_adjust+0x836/0x24a0 mm/mmap.c:962 vma_merge+0x860/0xeb0 mm/mmap.c:1217 madvise_update_vma+0x1b6/0x7f0 mm/madvise.c:180 madvise_vma_behavior+0x116/0x19d0 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 ffff888075796f00 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 4 bytes inside of 32-byte region [ffff888075796f00, ffff888075796f20) The buggy address belongs to the page: page:ffffea0001d5e580 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888075796740 pfn:0x75796 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea00007815c0 dead000000000003 ffff888010c41500 raw: ffff888075796740 0000000080400034 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 15678, ts 467031103892, free_ts 467023490342 prep_new_page mm/page_alloc.c:2489 [inline] get_page_from_freelist+0x13ea/0x31d0 mm/page_alloc.c:4219 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5435 alloc_pages+0x1aa/0x310 mm/mempolicy.c:2268 alloc_slab_page mm/slub.c:1799 [inline] allocate_slab mm/slub.c:1944 [inline] new_slab+0x295/0x400 mm/slub.c:2004 ___slab_alloc+0x7ed/0xe00 mm/slub.c:3018 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3105 slab_alloc_node mm/slub.c:3196 [inline] slab_alloc mm/slub.c:3238 [inline] kmem_cache_alloc_trace+0x289/0x2c0 mm/slub.c:3255 kmalloc include/linux/slab.h:581 [inline] kzalloc include/linux/slab.h:715 [inline] alloc_workqueue_attrs+0x38/0x80 kernel/workqueue.c:3387 apply_wqattrs_prepare+0xbc/0x890 kernel/workqueue.c:3959 apply_workqueue_attrs_locked+0xc1/0x140 kernel/workqueue.c:4068 apply_workqueue_attrs kernel/workqueue.c:4105 [inline] alloc_and_link_pwqs kernel/workqueue.c:4223 [inline] alloc_workqueue+0xa48/0xf00 kernel/workqueue.c:4337 tipc_topsrv_work_start net/tipc/topsrv.c:621 [inline] tipc_topsrv_start net/tipc/topsrv.c:665 [inline] tipc_topsrv_init_net+0x4ff/0xb90 net/tipc/topsrv.c:710 ops_init+0xaf/0x470 net/core/net_namespace.c:140 setup_net+0x554/0xbb0 net/core/net_namespace.c:331 copy_net_ns+0x318/0x760 net/core/net_namespace.c:477 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1356 [inline] free_pcp_prepare+0x549/0xd20 mm/page_alloc.c:1406 free_unref_page_prepare mm/page_alloc.c:3376 [inline] free_unref_page+0x19/0x6c0 mm/page_alloc.c:3455 __vunmap+0x798/0xc50 mm/vmalloc.c:2659 __vfree+0x3c/0xd0 mm/vmalloc.c:2707 vfree+0x5a/0x90 mm/vmalloc.c:2738 copy_entries_to_user net/ipv4/netfilter/ip_tables.c:868 [inline] get_entries net/ipv4/netfilter/ip_tables.c:1024 [inline] do_ipt_get_ctl+0x7fe/0x9d0 net/ipv4/netfilter/ip_tables.c:1663 nf_getsockopt+0x72/0xd0 net/netfilter/nf_sockopt.c:116 ip_getsockopt net/ipv4/ip_sockglue.c:1786 [inline] ip_getsockopt+0x164/0x1c0 net/ipv4/ip_sockglue.c:1765 tcp_getsockopt+0x86/0xd0 net/ipv4/tcp.c:4287 __sys_getsockopt+0x21f/0x6a0 net/socket.c:2224 __do_sys_getsockopt net/socket.c:2239 [inline] __se_sys_getsockopt net/socket.c:2236 [inline] __x64_sys_getsockopt+0xba/0x150 net/socket.c:2236 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 Memory state around the buggy address: ffff888075796e00: fb fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc ffff888075796e80: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc >ffff888075796f00: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc ^ ffff888075796f80: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc ffff888075797000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================