================================================================== BUG: KASAN: use-after-free in do_shrink_slab+0xb15/0xbd0 mm/vmscan.c:774 Read of size 8 at addr ffff888077d3d5b8 by task syz-executor.0/8569 CPU: 0 PID: 8569 Comm: syz-executor.0 Not tainted 6.0.0-syzkaller-09589-g55be6084c8e0 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:317 [inline] print_report.cold+0x2ba/0x719 mm/kasan/report.c:433 kasan_report+0xb1/0x1e0 mm/kasan/report.c:495 do_shrink_slab+0xb15/0xbd0 mm/vmscan.c:774 shrink_slab+0x17c/0x6f0 mm/vmscan.c:991 drop_slab_node mm/vmscan.c:1026 [inline] drop_slab+0x104/0x280 mm/vmscan.c:1036 drop_caches_sysctl_handler+0xf6/0x110 fs/drop_caches.c:66 proc_sys_call_handler+0x49c/0x6d0 fs/proc/proc_sysctl.c:611 call_write_iter include/linux/fs.h:2190 [inline] do_iter_readv_writev+0x20b/0x3b0 fs/read_write.c:735 do_iter_write+0x182/0x700 fs/read_write.c:861 vfs_iter_write+0x70/0xa0 fs/read_write.c:902 iter_file_splice_write+0x741/0xc90 fs/splice.c:686 do_splice_from fs/splice.c:764 [inline] direct_splice_actor+0x110/0x180 fs/splice.c:931 splice_direct_to_actor+0x331/0x8a0 fs/splice.c:886 do_splice_direct+0x1a7/0x270 fs/splice.c:974 do_sendfile+0xb19/0x1270 fs/read_write.c:1255 __do_compat_sys_sendfile fs/read_write.c:1338 [inline] __se_compat_sys_sendfile fs/read_write.c:1327 [inline] __ia32_compat_sys_sendfile+0x159/0x220 fs/read_write.c:1327 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 RIP: 0023:0xf7fb5549 Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f7f8f5cc EFLAGS: 00000296 ORIG_RAX: 00000000000000bb RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000000005 RDX: 0000000020002080 RSI: 0000000000000870 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 8518: 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:437 [inline] ____kasan_kmalloc mm/kasan/common.c:516 [inline] ____kasan_kmalloc mm/kasan/common.c:475 [inline] __kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:525 kmalloc include/linux/slab.h:605 [inline] kzalloc include/linux/slab.h:733 [inline] ops_init+0xfb/0x470 net/core/net_namespace.c:124 setup_net+0x5d1/0xc50 net/core/net_namespace.c:325 copy_net_ns+0x318/0x760 net/core/net_namespace.c:471 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110 copy_namespaces+0x391/0x450 kernel/nsproxy.c:178 copy_process+0x307b/0x7110 kernel/fork.c:2257 kernel_clone+0xe7/0x8f0 kernel/fork.c:2672 __do_compat_sys_ia32_clone+0x9e/0xd0 arch/x86/kernel/sys_ia32.c:254 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 Freed by task 8518: 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:367 [inline] ____kasan_slab_free+0x166/0x1c0 mm/kasan/common.c:329 kasan_slab_free include/linux/kasan.h:200 [inline] slab_free_hook mm/slub.c:1759 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1785 slab_free mm/slub.c:3539 [inline] kfree+0xe2/0x580 mm/slub.c:4567 ops_init+0xcd/0x470 net/core/net_namespace.c:139 setup_net+0x5d1/0xc50 net/core/net_namespace.c:325 copy_net_ns+0x318/0x760 net/core/net_namespace.c:471 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110 copy_namespaces+0x391/0x450 kernel/nsproxy.c:178 copy_process+0x307b/0x7110 kernel/fork.c:2257 kernel_clone+0xe7/0x8f0 kernel/fork.c:2672 __do_compat_sys_ia32_clone+0x9e/0xd0 arch/x86/kernel/sys_ia32.c:254 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 Last potentially related work creation: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 __kasan_record_aux_stack+0xbe/0xd0 mm/kasan/generic.c:348 call_rcu+0x99/0x790 kernel/rcu/tree.c:2796 qdisc_put+0xcd/0xe0 net/sched/sch_generic.c:1082 shutdown_scheduler_queue net/sched/sch_generic.c:1135 [inline] netdev_for_each_tx_queue include/linux/netdevice.h:2440 [inline] dev_shutdown+0x11a/0x520 net/sched/sch_generic.c:1467 unregister_netdevice_many+0x90e/0x1980 net/core/dev.c:10834 unregister_netdevice_queue+0x2dd/0x3c0 net/core/dev.c:10774 unregister_netdevice include/linux/netdevice.h:3032 [inline] __tun_detach+0x111d/0x1480 drivers/net/tun.c:684 tun_detach drivers/net/tun.c:701 [inline] tun_chr_close+0xc4/0x180 drivers/net/tun.c:3458 __fput+0x27c/0xa90 fs/file_table.c:320 task_work_run+0xdd/0x1a0 kernel/task_work.c:177 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop kernel/entry/common.c:169 [inline] exit_to_user_mode_prepare+0x23c/0x250 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline] syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:294 __do_fast_syscall_32+0x72/0xf0 arch/x86/entry/common.c:181 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 Second to last potentially related work creation: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 __kasan_record_aux_stack+0xbe/0xd0 mm/kasan/generic.c:348 call_rcu+0x99/0x790 kernel/rcu/tree.c:2796 netlink_release+0xeff/0x1db0 net/netlink/af_netlink.c:815 __sock_release net/socket.c:650 [inline] sock_release+0x87/0x1b0 net/socket.c:678 netlink_kernel_release+0x4b/0x60 net/netlink/af_netlink.c:2107 uevent_net_exit+0xbd/0x290 lib/kobject_uevent.c:799 ops_exit_list+0xb0/0x170 net/core/net_namespace.c:162 cleanup_net+0x4ea/0xb00 net/core/net_namespace.c:594 process_one_work+0x991/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 The buggy address belongs to the object at ffff888077d3d000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1464 bytes inside of 2048-byte region [ffff888077d3d000, ffff888077d3d800) The buggy address belongs to the physical page: page:ffffea0001df4e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x77d38 head:ffffea0001df4e00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 ffffea000079fe00 dead000000000002 ffff888011842000 raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0x152800(GFP_NOWAIT|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL), pid 28491, tgid 28485 (syz-executor.4), ts 1101791428385, free_ts 1101448616672 prep_new_page mm/page_alloc.c:2532 [inline] get_page_from_freelist+0x109b/0x2ce0 mm/page_alloc.c:4283 __alloc_pages+0x1c7/0x510 mm/page_alloc.c:5549 alloc_pages+0x1a6/0x270 mm/mempolicy.c:2270 alloc_slab_page mm/slub.c:1829 [inline] allocate_slab+0x27e/0x3d0 mm/slub.c:1974 new_slab mm/slub.c:2034 [inline] ___slab_alloc+0x84f/0xe80 mm/slub.c:3036 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3123 slab_alloc_node mm/slub.c:3214 [inline] kmem_cache_alloc_node_trace+0x185/0x410 mm/slub.c:3312 kmalloc_node include/linux/slab.h:618 [inline] kzalloc_node include/linux/slab.h:744 [inline] throtl_pd_alloc+0xc4/0xa80 block/blk-throttle.c:345 blkg_alloc+0x5f6/0x890 block/blk-cgroup.c:250 blkg_create+0xcf9/0x1260 block/blk-cgroup.c:292 blkg_lookup_create block/blk-cgroup.c:405 [inline] blkg_tryget_closest block/blk-cgroup.c:1855 [inline] bio_associate_blkg_from_css+0xda1/0x1280 block/blk-cgroup.c:1889 bio_associate_blkg+0xc6/0x210 block/blk-cgroup.c:1917 bio_init+0x27b/0x560 block/bio.c:260 bio_alloc_bioset+0x255/0x790 block/bio.c:545 bio_alloc include/linux/bio.h:423 [inline] submit_bh_wbc+0x281/0x650 fs/buffer.c:2699 submit_bh fs/buffer.c:2724 [inline] block_read_full_folio+0x63e/0x9d0 fs/buffer.c:2340 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1449 [inline] free_pcp_prepare+0x5e4/0xd20 mm/page_alloc.c:1499 free_unref_page_prepare mm/page_alloc.c:3380 [inline] free_unref_page+0x19/0x4d0 mm/page_alloc.c:3476 __unfreeze_partials+0x17c/0x1a0 mm/slub.c:2553 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:447 kasan_slab_alloc include/linux/kasan.h:224 [inline] slab_post_alloc_hook mm/slab.h:727 [inline] slab_alloc_node mm/slub.c:3248 [inline] slab_alloc mm/slub.c:3256 [inline] __kmalloc+0x28a/0x340 mm/slub.c:4425 kmalloc_array include/linux/slab.h:640 [inline] kcalloc include/linux/slab.h:671 [inline] iter_file_splice_write+0x168/0xc90 fs/splice.c:625 do_splice_from fs/splice.c:764 [inline] direct_splice_actor+0x110/0x180 fs/splice.c:931 splice_direct_to_actor+0x331/0x8a0 fs/splice.c:886 do_splice_direct+0x1a7/0x270 fs/splice.c:974 do_sendfile+0xb19/0x1270 fs/read_write.c:1255 __do_compat_sys_sendfile fs/read_write.c:1338 [inline] __se_compat_sys_sendfile fs/read_write.c:1327 [inline] __ia32_compat_sys_sendfile+0x159/0x220 fs/read_write.c:1327 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 Memory state around the buggy address: ffff888077d3d480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888077d3d500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888077d3d580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888077d3d600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888077d3d680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ---------------- Code disassembly (best guess): 0: 03 74 c0 01 add 0x1(%rax,%rax,8),%esi 4: 10 05 03 74 b8 01 adc %al,0x1b87403(%rip) # 0x1b8740d a: 10 06 adc %al,(%rsi) c: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 10: 10 07 adc %al,(%rdi) 12: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi 16: 10 08 adc %cl,(%rax) 18: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1c: 00 00 add %al,(%rax) 1e: 00 00 add %al,(%rax) 20: 00 51 52 add %dl,0x52(%rcx) 23: 55 push %rbp 24: 89 e5 mov %esp,%ebp 26: 0f 34 sysenter 28: cd 80 int $0x80 * 2a: 5d pop %rbp <-- trapping instruction 2b: 5a pop %rdx 2c: 59 pop %rcx 2d: c3 retq 2e: 90 nop 2f: 90 nop 30: 90 nop 31: 90 nop 32: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 39: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi