================================================================== BUG: KASAN: slab-use-after-free in iov_iter_folioq_advance+0x10c/0x360 lib/iov_iter.c:540 Read of size 8 at addr ffff888033ca0520 by task syz.0.1774/20861 CPU: 0 UID: 0 PID: 20861 Comm: syz.0.1774 Not tainted 6.11.0-syzkaller-02574-ga430d95c5efa #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 Call Trace: __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 iov_iter_folioq_advance+0x10c/0x360 lib/iov_iter.c:540 netfs_write_folio+0x154b/0x1fe0 fs/netfs/write_issue.c:481 netfs_writepages+0x89f/0xe80 fs/netfs/write_issue.c:541 do_writepages+0x35f/0x870 mm/page-writeback.c:2683 filemap_fdatawrite_wbc+0x125/0x180 mm/filemap.c:397 __filemap_fdatawrite_range mm/filemap.c:430 [inline] __filemap_fdatawrite mm/filemap.c:436 [inline] filemap_fdatawrite+0xfb/0x160 mm/filemap.c:441 v9fs_vfs_setattr+0x7e5/0xe20 fs/9p/vfs_inode.c:1037 notify_change+0xbcc/0xe90 fs/attr.c:503 chown_common+0x501/0x850 fs/open.c:793 do_fchownat+0x16a/0x240 fs/open.c:824 __do_sys_chown fs/open.c:844 [inline] __se_sys_chown fs/open.c:842 [inline] __x64_sys_chown+0x82/0x90 fs/open.c:842 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb05977def9 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:00007fb05a5eb038 EFLAGS: 00000246 ORIG_RAX: 000000000000005c RAX: ffffffffffffffda RBX: 00007fb059936058 RCX: 00007fb05977def9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000080 RBP: 00007fb0597f0b76 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007fb059936058 R15: 00007ffd2a2fa8f8 Allocated by task 20861: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:370 [inline] __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387 kasan_kmalloc include/linux/kasan.h:211 [inline] __kmalloc_cache_noprof+0x19c/0x2c0 mm/slub.c:4190 kmalloc_noprof include/linux/slab.h:690 [inline] netfs_buffer_append_folio+0x1f1/0x8b0 fs/netfs/misc.c:25 netfs_write_folio+0xe69/0x1fe0 fs/netfs/write_issue.c:421 netfs_writepages+0x89f/0xe80 fs/netfs/write_issue.c:541 do_writepages+0x35f/0x870 mm/page-writeback.c:2683 filemap_fdatawrite_wbc+0x125/0x180 mm/filemap.c:397 __filemap_fdatawrite_range mm/filemap.c:430 [inline] __filemap_fdatawrite mm/filemap.c:436 [inline] filemap_fdatawrite+0xfb/0x160 mm/filemap.c:441 v9fs_vfs_setattr+0x7e5/0xe20 fs/9p/vfs_inode.c:1037 notify_change+0xbcc/0xe90 fs/attr.c:503 chown_common+0x501/0x850 fs/open.c:793 do_fchownat+0x16a/0x240 fs/open.c:824 __do_sys_chown fs/open.c:844 [inline] __se_sys_chown fs/open.c:842 [inline] __x64_sys_chown+0x82/0x90 fs/open.c:842 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 7578: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579 poison_slab_object+0xe0/0x150 mm/kasan/common.c:240 __kasan_slab_free+0x37/0x60 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2250 [inline] slab_free mm/slub.c:4474 [inline] kfree+0x149/0x360 mm/slub.c:4595 netfs_delete_buffer_head+0x9f/0xd0 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+0x1b9a/0x4950 fs/netfs/write_collect.c:551 process_one_work kernel/workqueue.c:3231 [inline] process_scheduled_works+0xa2e/0x1830 kernel/workqueue.c:3312 worker_thread+0x870/0xd30 kernel/workqueue.c:3393 kthread+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/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 ffff888033ca0400 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 288 bytes inside of freed 512-byte region [ffff888033ca0400, ffff888033ca0600) The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x33ca0 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: 0xfdffffff(slab) raw: 00fff00000000040 ffff88801ac41c80 ffffea0000917800 dead000000000002 raw: 0000000000000000 0000000080100010 00000001fdffffff 0000000000000000 head: 00fff00000000040 ffff88801ac41c80 ffffea0000917800 dead000000000002 head: 0000000000000000 0000000080100010 00000001fdffffff 0000000000000000 head: 00fff00000000002 ffffea0000cf2801 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 11, tgid 11 (kworker/u8:0), ts 80851962474, free_ts 80833458896 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1500 prep_new_page mm/page_alloc.c:1508 [inline] get_page_from_freelist+0x2e4c/0x2f10 mm/page_alloc.c:3446 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4702 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline] alloc_pages_node_noprof include/linux/gfp.h:296 [inline] alloc_slab_page+0x5f/0x120 mm/slub.c:2319 allocate_slab+0x5a/0x2f0 mm/slub.c:2482 new_slab mm/slub.c:2535 [inline] ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3721 __slab_alloc+0x58/0xa0 mm/slub.c:3811 __slab_alloc_node mm/slub.c:3864 [inline] slab_alloc_node mm/slub.c:4026 [inline] __kmalloc_cache_noprof+0x1d5/0x2c0 mm/slub.c:4185 kmalloc_noprof include/linux/slab.h:690 [inline] kzalloc_noprof include/linux/slab.h:816 [inline] mca_alloc net/ipv6/mcast.c:881 [inline] __ipv6_dev_mc_inc+0x429/0xaa0 net/ipv6/mcast.c:937 addrconf_join_solict net/ipv6/addrconf.c:2241 [inline] addrconf_dad_begin net/ipv6/addrconf.c:4104 [inline] addrconf_dad_work+0x448/0x16f0 net/ipv6/addrconf.c:4229 process_one_work kernel/workqueue.c:3231 [inline] process_scheduled_works+0xa2e/0x1830 kernel/workqueue.c:3312 worker_thread+0x870/0xd30 kernel/workqueue.c:3393 kthread+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 page last free pid 5229 tgid 5229 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1101 [inline] free_unref_page+0xd22/0xea0 mm/page_alloc.c:2619 discard_slab mm/slub.c:2581 [inline] __put_partials+0xeb/0x130 mm/slub.c:3049 put_cpu_partial+0x17c/0x250 mm/slub.c:3124 __slab_free+0x2ea/0x3d0 mm/slub.c:4344 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9e/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:322 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slub.c:3989 [inline] slab_alloc_node mm/slub.c:4038 [inline] __do_kmalloc_node mm/slub.c:4158 [inline] __kmalloc_noprof+0x1a6/0x400 mm/slub.c:4171 kmalloc_noprof include/linux/slab.h:694 [inline] kzalloc_noprof include/linux/slab.h:816 [inline] fib6_info_alloc+0x2e/0xf0 net/ipv6/ip6_fib.c:155 ip6_route_info_create+0x445/0x12b0 net/ipv6/route.c:3761 ip6_route_add+0x28/0x160 net/ipv6/route.c:3853 addrconf_prefix_route net/ipv6/addrconf.c:2486 [inline] add_v4_addrs+0xb5a/0x1160 net/ipv6/addrconf.c:3271 addrconf_gre_config net/ipv6/addrconf.c:3546 [inline] addrconf_init_auto_addrs+0x208/0xeb0 net/ipv6/addrconf.c:3564 addrconf_notify+0xaff/0x1020 net/ipv6/addrconf.c:3745 notifier_call_chain+0x1a1/0x3e0 kernel/notifier.c:93 __dev_notify_flags+0x207/0x400 Memory state around the buggy address: ffff888033ca0400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888033ca0480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888033ca0500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888033ca0580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888033ca0600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================