================================================================== BUG: KASAN: slab-use-after-free in iov_iter_folioq_advance lib/iov_iter.c:540 [inline] BUG: KASAN: slab-use-after-free in iov_iter_advance+0x677/0x6c0 lib/iov_iter.c:576 Read of size 8 at addr ffff888031b27d20 by task syz.4.766/9444 CPU: 0 UID: 0 PID: 9444 Comm: syz.4.766 Not tainted 6.11.0-syzkaller-11558-g075dbe9f6e3c #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 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 iov_iter_folioq_advance lib/iov_iter.c:540 [inline] iov_iter_advance+0x677/0x6c0 lib/iov_iter.c:576 netfs_write_folio+0x745/0x18f0 fs/netfs/write_issue.c:481 netfs_writepages+0x2ba/0xb90 fs/netfs/write_issue.c:541 do_writepages+0x1a6/0x7f0 mm/page-writeback.c:2683 filemap_fdatawrite_wbc mm/filemap.c:398 [inline] filemap_fdatawrite_wbc+0x148/0x1c0 mm/filemap.c:388 __filemap_fdatawrite_range+0xb3/0xf0 mm/filemap.c:431 v9fs_dir_release+0x429/0x590 fs/9p/vfs_dir.c:219 __fput+0x3f9/0xb60 fs/file_table.c:431 task_work_run+0x151/0x250 kernel/task_work.c:228 get_signal+0x1ca/0x2770 kernel/signal.c:2690 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [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+0x150/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb224f7df39 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fb225d8f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: 0000000000413000 RBX: 00007fb225135f80 RCX: 00007fb224f7df39 RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000007 RBP: 00007fb224ff0216 R08: 0000000000000000 R09: 0000000000000000 R10: 000000007ffff000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fb225135f80 R15: 00007ffd416b8088 Allocated by task 9444: 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:377 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394 kmalloc_noprof include/linux/slab.h:878 [inline] netfs_buffer_append_folio+0x181/0x750 fs/netfs/misc.c:25 netfs_write_folio+0x542/0x18f0 fs/netfs/write_issue.c:421 netfs_writepages+0x2ba/0xb90 fs/netfs/write_issue.c:541 do_writepages+0x1a6/0x7f0 mm/page-writeback.c:2683 filemap_fdatawrite_wbc mm/filemap.c:398 [inline] filemap_fdatawrite_wbc+0x148/0x1c0 mm/filemap.c:388 __filemap_fdatawrite_range+0xb3/0xf0 mm/filemap.c:431 v9fs_dir_release+0x429/0x590 fs/9p/vfs_dir.c:219 __fput+0x3f9/0xb60 fs/file_table.c:431 task_work_run+0x151/0x250 kernel/task_work.c:228 get_signal+0x1ca/0x2770 kernel/signal.c:2690 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [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+0x150/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 11: 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 mm/kasan/common.c:247 [inline] __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:2343 [inline] slab_free mm/slub.c:4580 [inline] kfree+0x14f/0x4b0 mm/slub.c:4728 netfs_delete_buffer_head+0xa6/0x100 fs/netfs/misc.c:59 netfs_writeback_unlock_folios fs/netfs/write_collect.c:139 [inline] netfs_collect_write_results fs/netfs/write_collect.c:493 [inline] netfs_write_collection_worker+0x20f9/0x4f80 fs/netfs/write_collect.c:551 process_one_work+0x9c8/0x1ba0 kernel/workqueue.c:3229 process_scheduled_works kernel/workqueue.c:3310 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391 kthread+0x2c4/0x3a0 kernel/kthread.c:389 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 The buggy address belongs to the object at ffff888031b27c00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 288 bytes inside of freed 512-byte region [ffff888031b27c00, ffff888031b27e00) The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x31b24 head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801b041c80 ffffea0001706b00 dead000000000002 raw: 0000000000000000 0000000080100010 00000001f5000000 0000000000000000 head: 00fff00000000040 ffff88801b041c80 ffffea0001706b00 dead000000000002 head: 0000000000000000 0000000080100010 00000001f5000000 0000000000000000 head: 00fff00000000002 ffffea0000c6c901 ffffffffffffffff 0000000000000000 head: 0000000000000004 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5232, tgid 5232 (syz-executor), ts 85071076020, free_ts 85015466024 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1537 prep_new_page mm/page_alloc.c:1545 [inline] get_page_from_freelist+0x101e/0x3070 mm/page_alloc.c:3457 __alloc_pages_noprof+0x223/0x25c0 mm/page_alloc.c:4733 alloc_pages_mpol_noprof+0x275/0x610 mm/mempolicy.c:2265 alloc_slab_page mm/slub.c:2413 [inline] allocate_slab mm/slub.c:2579 [inline] new_slab+0x28b/0x3f0 mm/slub.c:2632 ___slab_alloc+0xd1d/0x16f0 mm/slub.c:3819 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3909 __slab_alloc_node mm/slub.c:3962 [inline] slab_alloc_node mm/slub.c:4123 [inline] __do_kmalloc_node mm/slub.c:4264 [inline] __kmalloc_noprof+0x367/0x400 mm/slub.c:4277 kmalloc_noprof include/linux/slab.h:882 [inline] kzalloc_noprof include/linux/slab.h:1014 [inline] fib6_info_alloc+0x40/0x160 net/ipv6/ip6_fib.c:155 ip6_route_info_create+0x337/0x1910 net/ipv6/route.c:3761 ip6_route_add+0x26/0x1c0 net/ipv6/route.c:3853 addrconf_add_mroute+0x1de/0x350 net/ipv6/addrconf.c:2550 addrconf_add_dev+0x14e/0x1c0 net/ipv6/addrconf.c:2568 addrconf_dev_config net/ipv6/addrconf.c:3484 [inline] addrconf_init_auto_addrs+0x380/0x820 net/ipv6/addrconf.c:3572 addrconf_notify+0xe91/0x19c0 net/ipv6/addrconf.c:3745 notifier_call_chain+0xbc/0x410 kernel/notifier.c:93 page last free pid 5225 tgid 5225 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1108 [inline] free_unref_page+0x5f4/0xdc0 mm/page_alloc.c:2638 __put_partials+0x14c/0x170 mm/slub.c:3146 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4e/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:247 [inline] slab_post_alloc_hook mm/slub.c:4086 [inline] slab_alloc_node mm/slub.c:4135 [inline] kmem_cache_alloc_lru_noprof+0x121/0x2f0 mm/slub.c:4154 sock_alloc_inode+0x25/0x1c0 net/socket.c:308 alloc_inode+0x60/0x230 fs/inode.c:263 sock_alloc+0x40/0x280 net/socket.c:634 __sock_create+0xc0/0x800 net/socket.c:1541 sock_create net/socket.c:1628 [inline] __sys_socket_create net/socket.c:1665 [inline] __sys_socket+0x14f/0x260 net/socket.c:1712 __do_sys_socket net/socket.c:1726 [inline] __se_sys_socket net/socket.c:1724 [inline] __x64_sys_socket+0x72/0xb0 net/socket.c:1724 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888031b27c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888031b27c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888031b27d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888031b27d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888031b27e00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================