================================================================== BUG: KASAN: use-after-free in strcmp+0x66/0xa0 lib/string.c:346 Read of size 1 at addr ffff888018b592c4 by task syz-executor997/3589 CPU: 1 PID: 3589 Comm: syz-executor997 Not tainted 5.17.0-rc3-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+0x1dc/0x2d8 lib/dump_stack.c:106 print_address_description+0x65/0x3a0 mm/kasan/report.c:255 __kasan_report mm/kasan/report.c:442 [inline] kasan_report+0x19a/0x1f0 mm/kasan/report.c:459 strcmp+0x66/0xa0 lib/string.c:346 replace_vma_anon_name mm/madvise.c:141 [inline] madvise_update_vma+0x49d/0x7e0 mm/madvise.c:212 madvise_vma_behavior mm/madvise.c:1043 [inline] madvise_walk_vmas mm/madvise.c:1207 [inline] do_madvise+0xb6e/0x1200 mm/madvise.c:1385 __do_sys_madvise mm/madvise.c:1398 [inline] __se_sys_madvise mm/madvise.c:1396 [inline] __x64_sys_madvise+0xa2/0xb0 mm/madvise.c:1396 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fba2b6b7ff9 Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 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 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffdddc7a618 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fba2b6b7ff9 RDX: 000000000000000b RSI: 0000000000001000 RDI: 0000000020ffc000 RBP: 00007fba2b67bfe0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000020000000 R11: 0000000000000246 R12: 00007fba2b67c070 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 3589: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:436 [inline] ____kasan_kmalloc+0xdc/0x110 mm/kasan/common.c:515 kasan_kmalloc include/linux/kasan.h:270 [inline] __kmalloc+0x253/0x380 mm/slub.c:4424 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+0x584/0x7e0 mm/madvise.c:212 madvise_vma_anon_name mm/madvise.c:1236 [inline] madvise_walk_vmas mm/madvise.c:1207 [inline] madvise_set_anon_name+0x367/0x520 mm/madvise.c:1269 prctl_set_vma+0x19b/0x220 kernel/sys.c:2305 __do_sys_prctl+0x183/0x1120 kernel/sys.c:2594 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Freed by task 3589: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4c/0x70 mm/kasan/common.c:45 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:370 ____kasan_slab_free+0x126/0x180 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:236 [inline] slab_free_hook mm/slub.c:1728 [inline] slab_free_freelist_hook+0x12e/0x1a0 mm/slub.c:1754 slab_free mm/slub.c:3509 [inline] kfree+0xb8/0x2e0 mm/slub.c:4562 vm_area_free+0x11/0x30 kernel/fork.c:376 __vma_adjust+0x315d/0x3910 mm/mmap.c:962 vma_merge+0xd15/0x1020 madvise_update_vma+0x235/0x7e0 mm/madvise.c:180 madvise_vma_behavior mm/madvise.c:1043 [inline] madvise_walk_vmas mm/madvise.c:1207 [inline] do_madvise+0xb6e/0x1200 mm/madvise.c:1385 __do_sys_madvise mm/madvise.c:1398 [inline] __se_sys_madvise mm/madvise.c:1396 [inline] __x64_sys_madvise+0xa2/0xb0 mm/madvise.c:1396 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae The buggy address belongs to the object at ffff888018b592c0 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 4 bytes inside of 32-byte region [ffff888018b592c0, ffff888018b592e0) The buggy address belongs to the page: page:ffffea000062d640 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x18b59 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea000069d2c0 dead000000000003 ffff888011441500 raw: 0000000000000000 0000000080400040 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 22, ts 6054220736, free_ts 6053740729 prep_new_page mm/page_alloc.c:2434 [inline] get_page_from_freelist+0x729/0x9e0 mm/page_alloc.c:4165 __alloc_pages+0x255/0x580 mm/page_alloc.c:5389 alloc_slab_page mm/slub.c:1799 [inline] allocate_slab+0xce/0x3f0 mm/slub.c:1944 new_slab mm/slub.c:2004 [inline] ___slab_alloc+0x3fe/0xc30 mm/slub.c:3018 __slab_alloc mm/slub.c:3105 [inline] slab_alloc_node mm/slub.c:3196 [inline] slab_alloc mm/slub.c:3238 [inline] __kmalloc+0x2eb/0x380 mm/slub.c:4420 kmalloc include/linux/slab.h:586 [inline] shmem_initxattrs+0xcd/0x1e0 mm/shmem.c:3129 security_inode_init_security+0x2a2/0x3c0 security/security.c:1103 shmem_mknod+0xb0/0x1b0 mm/shmem.c:2818 vfs_mknod+0x3f5/0x5a0 fs/namei.c:3811 handle_create drivers/base/devtmpfs.c:228 [inline] handle drivers/base/devtmpfs.c:393 [inline] devtmpfs_work_loop+0x921/0x1080 drivers/base/devtmpfs.c:408 devtmpfsd+0x44/0x50 drivers/base/devtmpfs.c:450 kthread+0x2a3/0x2d0 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 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+0xd1c/0xe00 mm/page_alloc.c:1404 free_unref_page_prepare mm/page_alloc.c:3325 [inline] free_unref_page+0x7d/0x580 mm/page_alloc.c:3404 __vunmap+0x936/0xa80 mm/vmalloc.c:2635 free_work+0x66/0x90 mm/vmalloc.c:97 process_one_work+0x850/0x1130 kernel/workqueue.c:2307 worker_thread+0xab1/0x1300 kernel/workqueue.c:2454 kthread+0x2a3/0x2d0 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 Memory state around the buggy address: ffff888018b59180: 00 00 01 fc fc fc fc fc fb fb fb fb fc fc fc fc ffff888018b59200: 00 00 01 fc fc fc fc fc 00 00 01 fc fc fc fc fc >ffff888018b59280: 00 00 01 fc fc fc fc fc fa fb fb fb fc fc fc fc ^ ffff888018b59300: 00 00 01 fc fc fc fc fc fa fb fb fb fc fc fc fc ffff888018b59380: 00 00 01 fc fc fc fc fc 00 00 01 fc fc fc fc fc ==================================================================