Hi, We would like to report the following bug which has been found by our modified version of syzkaller. ====================================================== description: KASAN: invalid-free in __io_uring_register affected file: fs/io_uring.c kernel version: 5.19-rc6 kernel commit: 32346491ddf24599decca06190ebca03ff9de7f8 git tree: upstream kernel config: https://syzkaller.appspot.com/text?tag=KernelConfig&x=cd73026ceaed1402 crash reproducer: attached ====================================================== Crash log: ====================================================== BUG: KASAN: double-free or invalid-free in io_register_pbuf_ring fs/io_uring.c:12975 [inline] BUG: KASAN: double-free or invalid-free in __io_uring_register+0x16aa/0x19d0 fs/io_uring.c:13151 CPU: 1 PID: 16619 Comm: syz-executor.4 Tainted: G OE 5.19.0-rc6-g2eae0556bb9d #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 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:313 [inline] print_report.cold+0xe5/0x659 mm/kasan/report.c:429 kasan_report_invalid_free+0x5c/0x160 mm/kasan/report.c:458 ____kasan_slab_free mm/kasan/common.c:351 [inline] __kasan_slab_free+0x182/0x1a0 mm/kasan/common.c:379 kasan_slab_free include/linux/kasan.h:200 [inline] slab_free_hook mm/slub.c:1754 [inline] slab_free_freelist_hook mm/slub.c:1780 [inline] slab_free mm/slub.c:3536 [inline] kfree+0xec/0x4b0 mm/slub.c:4584 io_register_pbuf_ring fs/io_uring.c:12975 [inline] __io_uring_register+0x16aa/0x19d0 fs/io_uring.c:13151 __do_sys_io_uring_register fs/io_uring.c:13187 [inline] __se_sys_io_uring_register fs/io_uring.c:13167 [inline] __x64_sys_io_uring_register+0x2f2/0x650 fs/io_uring.c:13167 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+0x46/0xb0 RIP: 0033:0x7f7aa1a8d4ed Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 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:00007f7aa2b31be8 EFLAGS: 00000246 ORIG_RAX: 00000000000001ab RAX: ffffffffffffffda RBX: 00007f7aa1babf60 RCX: 00007f7aa1a8d4ed RDX: 0000000020000000 RSI: 0000000000000016 RDI: 0000000000000006 RBP: 00007f7aa1af92e1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff95597e6f R14: 00007f7aa1babf60 R15: 00007f7aa2b31d80 Allocated by task 16619: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:39 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:441 [inline] ____kasan_kmalloc mm/kasan/common.c:526 [inline] ____kasan_kmalloc mm/kasan/common.c:479 [inline] __kasan_kmalloc+0xb5/0xe0 mm/kasan/common.c:535 kasan_kmalloc include/linux/kasan.h:234 [inline] __kmalloc+0x1c9/0x4c0 mm/slub.c:4446 kcalloc include/linux/slab.h:671 [inline] io_init_bl_list.isra.0+0x24/0x102 fs/io_uring.c:5703 io_register_pbuf_ring fs/io_uring.c:12955 [inline] __io_uring_register.cold+0xd/0x10b5 fs/io_uring.c:13151 __do_sys_io_uring_register fs/io_uring.c:13187 [inline] __se_sys_io_uring_register fs/io_uring.c:13167 [inline] __x64_sys_io_uring_register+0x2f2/0x650 fs/io_uring.c:13167 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+0x46/0xb0 Last potentially related work creation: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:39 __kasan_record_aux_stack+0xbe/0xd0 mm/kasan/generic.c:356 call_rcu kernel/rcu/tree.c:3126 [inline] call_rcu+0x99/0x740 kernel/rcu/tree.c:3101 netlink_release+0xe42/0x1cb0 net/netlink/af_netlink.c:815 __sock_release+0xcd/0x280 net/socket.c:650 sock_close+0x18/0x20 net/socket.c:1365 __fput+0x277/0x9d0 fs/file_table.c:317 task_work_run+0xe0/0x1a0 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+0x253/0x260 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_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x46/0xb0 Second to last potentially related work creation: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:39 __kasan_record_aux_stack+0xbe/0xd0 mm/kasan/generic.c:356 call_rcu kernel/rcu/tree.c:3126 [inline] call_rcu+0x99/0x740 kernel/rcu/tree.c:3101 netlink_release+0xe42/0x1cb0 net/netlink/af_netlink.c:815 __sock_release+0xcd/0x280 net/socket.c:650 sock_close+0x18/0x20 net/socket.c:1365 __fput+0x277/0x9d0 fs/file_table.c:317 task_work_run+0xe0/0x1a0 kernel/task_work.c:177 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xb1e/0x2dd0 kernel/exit.c:797 do_group_exit+0xd2/0x2f0 kernel/exit.c:927 get_signal+0x2842/0x2870 kernel/signal.c:2857 arch_do_signal_or_restart+0x82/0x2270 arch/x86/kernel/signal.c:869 exit_to_user_mode_loop kernel/entry/common.c:166 [inline] exit_to_user_mode_prepare+0x174/0x260 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 ret_from_fork+0x15/0x30 arch/x86/entry/entry_64.S:295 The buggy address belongs to the object at ffff88815f2b7000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 256 bytes inside of 2048-byte region [ffff88815f2b7000, ffff88815f2b7800) The buggy address belongs to the physical page: page:ffffea00057cac00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x15f2b0 head:ffffea00057cac00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x17ff00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff) raw: 017ff00000010200 dead000000000100 dead000000000122 ffff888100042000 raw: 0000000000000000 0000000080080008 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 0xd2a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 6687, tgid 6687 (syz-executor.3), ts 55285345771, free_ts 54261940067 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook mm/page_alloc.c:2449 [inline] prep_new_page+0x297/0x330 mm/page_alloc.c:2456 get_page_from_freelist+0x2142/0x3c80 mm/page_alloc.c:4198 __alloc_pages+0x321/0x710 mm/page_alloc.c:5426 alloc_pages+0x119/0x250 mm/mempolicy.c:2272 alloc_slab_page mm/slub.c:1824 [inline] allocate_slab mm/slub.c:1969 [inline] new_slab+0x2a9/0x3f0 mm/slub.c:2029 ___slab_alloc+0xd5a/0x1140 mm/slub.c:3031 __slab_alloc.isra.0+0x4d/0xa0 mm/slub.c:3118 slab_alloc_node mm/slub.c:3209 [inline] __kmalloc_node_track_caller+0x321/0x440 mm/slub.c:4979 kmalloc_reserve+0x32/0xd0 net/core/skbuff.c:354 __alloc_skb+0x11f/0x370 net/core/skbuff.c:426 alloc_skb include/linux/skbuff.h:1426 [inline] nlmsg_new include/net/netlink.h:953 [inline] inet6_ifinfo_notify+0x72/0x150 net/ipv6/addrconf.c:6039 addrconf_notify+0x49b/0x1bb0 net/ipv6/addrconf.c:3653 notifier_call_chain+0xb5/0x200 kernel/notifier.c:87 call_netdevice_notifiers_info net/core/dev.c:1945 [inline] call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1930 call_netdevice_notifiers_extack net/core/dev.c:1983 [inline] call_netdevice_notifiers net/core/dev.c:1997 [inline] __dev_notify_flags+0x121/0x2c0 net/core/dev.c:8571 dev_change_flags+0x112/0x170 net/core/dev.c:8609 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1371 [inline] free_pcp_prepare+0x51f/0xd00 mm/page_alloc.c:1421 free_unref_page_prepare mm/page_alloc.c:3343 [inline] free_unref_page+0x19/0x5b0 mm/page_alloc.c:3438 __vunmap+0x6ff/0xaa0 mm/vmalloc.c:2665 __vfree+0x3c/0xd0 mm/vmalloc.c:2713 vfree+0x5a/0x90 mm/vmalloc.c:2744 kcov_put kernel/kcov.c:421 [inline] kcov_put+0x26/0x40 kernel/kcov.c:417 kcov_close+0xc/0x10 kernel/kcov.c:517 __fput+0x277/0x9d0 fs/file_table.c:317 task_work_run+0xe0/0x1a0 kernel/task_work.c:177 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xb1e/0x2dd0 kernel/exit.c:797 do_group_exit+0xd2/0x2f0 kernel/exit.c:927 __do_sys_exit_group kernel/exit.c:938 [inline] __se_sys_exit_group kernel/exit.c:936 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:936 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+0x46/0xb0 Memory state around the buggy address: ffff88815f2b7000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88815f2b7080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff88815f2b7100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ^ ffff88815f2b7180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88815f2b7200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ================================================================== -- Thanks and Regards, Dipanjan