================================================================== BUG: KASAN: slab-use-after-free in p9_fcall_init+0x1a9/0x1e0 net/9p/client.c:229 Read of size 8 at addr ffff88801a01c460 by task kworker/u32:12/5523 CPU: 2 PID: 5523 Comm: kworker/u32:12 Not tainted 6.9.0-syzkaller-11952-gc760b3725e52 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Workqueue: events_unbound netfs_write_collection_worker Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 print_address_description mm/kasan/report.c:377 [inline] print_report+0xc3/0x620 mm/kasan/report.c:488 kasan_report+0xd9/0x110 mm/kasan/report.c:601 p9_fcall_init+0x1a9/0x1e0 net/9p/client.c:229 p9_tag_alloc+0x21c/0x870 net/9p/client.c:298 p9_client_prepare_req+0x19f/0x4d0 net/9p/client.c:642 p9_client_rpc+0x1c3/0xc10 net/9p/client.c:689 p9_client_clunk+0x93/0x170 net/9p/client.c:1439 p9_fid_put include/net/9p/client.h:280 [inline] v9fs_free_request+0xdc/0x110 fs/9p/vfs_addr.c:138 netfs_free_request+0x22c/0x690 fs/netfs/objects.c:133 netfs_put_request+0x19b/0x1f0 fs/netfs/objects.c:165 netfs_write_collection_worker+0x19d0/0x59e0 fs/netfs/write_collect.c:701 process_one_work+0x958/0x1ad0 kernel/workqueue.c:3231 process_scheduled_works kernel/workqueue.c:3312 [inline] worker_thread+0x6c8/0xf70 kernel/workqueue.c:3393 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Allocated by task 7715: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:370 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:387 kmalloc_noprof include/linux/slab.h:660 [inline] p9_client_create+0xcf/0x11b0 net/9p/client.c:981 v9fs_session_init+0x1f8/0x1a80 fs/9p/v9fs.c:410 v9fs_mount+0xc6/0xaa0 fs/9p/vfs_super.c:122 legacy_get_tree+0x109/0x220 fs/fs_context.c:662 vfs_get_tree+0x8f/0x380 fs/super.c:1780 do_new_mount fs/namespace.c:3352 [inline] path_mount+0x6e1/0x1f10 fs/namespace.c:3679 do_mount fs/namespace.c:3692 [inline] __do_sys_mount fs/namespace.c:3898 [inline] __se_sys_mount fs/namespace.c:3875 [inline] __ia32_sys_mount+0x295/0x320 fs/namespace.c:3875 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e Freed by task 6106: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579 poison_slab_object+0xf7/0x160 mm/kasan/common.c:240 __kasan_slab_free+0x32/0x50 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2195 [inline] slab_free mm/slub.c:4436 [inline] kfree+0x12a/0x3b0 mm/slub.c:4557 p9_client_destroy+0x2e6/0x480 net/9p/client.c:1077 v9fs_session_close+0x49/0x2d0 fs/9p/v9fs.c:506 v9fs_kill_super+0x4d/0xa0 fs/9p/vfs_super.c:196 deactivate_locked_super+0xbe/0x1a0 fs/super.c:473 deactivate_super+0xde/0x100 fs/super.c:506 cleanup_mnt+0x222/0x450 fs/namespace.c:1267 task_work_run+0x14e/0x250 kernel/task_work.c:180 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x278/0x2a0 kernel/entry/common.c:218 __do_fast_syscall_32+0x80/0x120 arch/x86/entry/common.c:389 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e The buggy address belongs to the object at ffff88801a01c400 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 96 bytes inside of freed 512-byte region [ffff88801a01c400, ffff88801a01c600) The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88801a01f800 pfn:0x1a01c head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffefff(slab) raw: 00fff00000000040 ffff888015442c80 0000000000000000 dead000000000001 raw: ffff88801a01f800 000000008010000d 00000001ffffefff 0000000000000000 head: 00fff00000000040 ffff888015442c80 0000000000000000 dead000000000001 head: ffff88801a01f800 000000008010000d 00000001ffffefff 0000000000000000 head: 00fff00000000002 ffffea0000680701 ffffffffffffffff 0000000000000000 head: ffff888000000004 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5262, tgid 5262 (kworker/2:3), ts 50547680153, free_ts 50527022909 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1468 prep_new_page mm/page_alloc.c:1476 [inline] get_page_from_freelist+0x136a/0x2df0 mm/page_alloc.c:3402 __alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4660 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline] alloc_pages_node_noprof include/linux/gfp.h:296 [inline] alloc_slab_page+0x56/0x110 mm/slub.c:2264 allocate_slab mm/slub.c:2427 [inline] new_slab+0x84/0x260 mm/slub.c:2480 ___slab_alloc+0xdac/0x1870 mm/slub.c:3666 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3756 __slab_alloc_node mm/slub.c:3809 [inline] slab_alloc_node mm/slub.c:3988 [inline] __do_kmalloc_node mm/slub.c:4120 [inline] __kmalloc_noprof+0x37f/0x420 mm/slub.c:4134 kmalloc_noprof include/linux/slab.h:664 [inline] kzalloc_noprof include/linux/slab.h:778 [inline] fib6_info_alloc+0x40/0x160 net/ipv6/ip6_fib.c:155 ip6_route_info_create+0x337/0x1ae0 net/ipv6/route.c:3759 ip6_route_add+0x26/0x190 net/ipv6/route.c:3851 addrconf_prefix_route+0x2fe/0x510 net/ipv6/addrconf.c:2485 addrconf_add_linklocal+0x32a/0x650 net/ipv6/addrconf.c:3316 addrconf_addr_gen+0x37b/0x3d0 net/ipv6/addrconf.c:3445 addrconf_dev_config net/ipv6/addrconf.c:3491 [inline] addrconf_init_auto_addrs+0x446/0x820 net/ipv6/addrconf.c:3569 addrconf_notify+0x6ef/0x19e0 net/ipv6/addrconf.c:3742 page last free pid 5221 tgid 5221 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1088 [inline] free_unref_page+0x64a/0xe40 mm/page_alloc.c:2565 __put_partials+0x14c/0x170 mm/slub.c:2994 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4e/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:322 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slub.c:3940 [inline] slab_alloc_node mm/slub.c:4000 [inline] kmem_cache_alloc_node_noprof+0x153/0x310 mm/slub.c:4043 __alloc_skb+0x2b3/0x380 net/core/skbuff.c:656 alloc_skb include/linux/skbuff.h:1308 [inline] netlink_alloc_large_skb+0x69/0x130 net/netlink/af_netlink.c:1210 netlink_sendmsg+0x689/0xd70 net/netlink/af_netlink.c:1880 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] __sys_sendto+0x47f/0x4e0 net/socket.c:2192 __do_compat_sys_socketcall+0x5e2/0x700 net/compat.c:475 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e Memory state around the buggy address: ffff88801a01c300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88801a01c380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88801a01c400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88801a01c480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801a01c500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================