================================================================== BUG: KASAN: slab-out-of-bounds in iov_iter_revert+0x1da/0x5f0 lib/iov_iter.c:633 Read of size 4 at addr ffff88807a3bd9f8 by task kworker/u8:2/36 CPU: 1 UID: 0 PID: 36 Comm: kworker/u8:2 Not tainted 6.15.0-rc4-syzkaller-00147-gebd297a2affa #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 Workqueue: events_unbound netfs_write_collection_worker Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0xb4/0x290 mm/kasan/report.c:521 kasan_report+0x118/0x150 mm/kasan/report.c:634 iov_iter_revert+0x1da/0x5f0 lib/iov_iter.c:633 netfs_retry_write_stream fs/netfs/write_retry.c:44 [inline] netfs_retry_writes+0x1645/0x1840 fs/netfs/write_retry.c:231 netfs_collect_write_results fs/netfs/write_collect.c:352 [inline] netfs_write_collection_worker+0x2007/0x2bd0 fs/netfs/write_collect.c:374 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xadb/0x17a0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 9445: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4372 kmalloc_noprof include/linux/slab.h:905 [inline] slab_free_hook mm/slub.c:2350 [inline] slab_free mm/slub.c:4656 [inline] kmem_cache_free+0x169/0x3f0 mm/slub.c:4758 p9_req_put+0x19b/0x1f0 net/9p/client.c:409 p9_client_open+0x2a4/0x3c0 net/9p/client.c:1268 v9fs_file_open+0x36d/0x990 fs/9p/vfs_file.c:71 do_dentry_open+0xdf0/0x1970 fs/open.c:956 vfs_open+0x3b/0x340 fs/open.c:1086 do_open fs/namei.c:3880 [inline] path_openat+0x2ee5/0x3830 fs/namei.c:4039 do_filp_open+0x1fa/0x410 fs/namei.c:4066 do_sys_openat2+0x121/0x1c0 fs/open.c:1429 do_sys_open fs/open.c:1444 [inline] __do_sys_creat fs/open.c:1522 [inline] __se_sys_creat fs/open.c:1516 [inline] __x64_sys_creat+0x8f/0xc0 fs/open.c:1516 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 5873: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2398 [inline] slab_free mm/slub.c:4656 [inline] kfree+0x193/0x440 mm/slub.c:4855 slab_free_after_rcu_debug+0x62/0x290 mm/slub.c:4693 rcu_do_batch kernel/rcu/tree.c:2568 [inline] rcu_core+0xca5/0x1710 kernel/rcu/tree.c:2824 handle_softirqs+0x283/0x870 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] invoke_softirq kernel/softirq.c:453 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 Last potentially related work creation: kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47 kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:548 __call_rcu_common kernel/rcu/tree.c:3082 [inline] call_rcu+0x142/0x990 kernel/rcu/tree.c:3202 slab_free_hook mm/slub.c:2362 [inline] slab_free mm/slub.c:4656 [inline] kmem_cache_free+0x301/0x3f0 mm/slub.c:4758 p9_req_put+0x19b/0x1f0 net/9p/client.c:409 p9_client_open+0x2a4/0x3c0 net/9p/client.c:1268 v9fs_file_open+0x36d/0x990 fs/9p/vfs_file.c:71 do_dentry_open+0xdf0/0x1970 fs/open.c:956 vfs_open+0x3b/0x340 fs/open.c:1086 do_open fs/namei.c:3880 [inline] path_openat+0x2ee5/0x3830 fs/namei.c:4039 do_filp_open+0x1fa/0x410 fs/namei.c:4066 do_sys_openat2+0x121/0x1c0 fs/open.c:1429 do_sys_open fs/open.c:1444 [inline] __do_sys_creat fs/open.c:1522 [inline] __se_sys_creat fs/open.c:1516 [inline] __x64_sys_creat+0x8f/0xc0 fs/open.c:1516 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88807a3bd9c0 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 24 bytes to the right of allocated 32-byte region [ffff88807a3bd9c0, ffff88807a3bd9e0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7a3bd ksm flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88801a041780 ffffea0000976340 dead000000000003 raw: 0000000000000000 0000000000400040 00000000f5000000 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5814, tgid 5814 (syz-executor), ts 87394065168, free_ts 87161276245 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1d8/0x230 mm/page_alloc.c:1718 prep_new_page mm/page_alloc.c:1726 [inline] get_page_from_freelist+0x21c7/0x22a0 mm/page_alloc.c:3688 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4970 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2301 alloc_slab_page mm/slub.c:2468 [inline] allocate_slab+0x8a/0x3b0 mm/slub.c:2632 new_slab mm/slub.c:2686 [inline] ___slab_alloc+0xbfc/0x1480 mm/slub.c:3872 __slab_alloc mm/slub.c:3962 [inline] __slab_alloc_node mm/slub.c:4037 [inline] slab_alloc_node mm/slub.c:4198 [inline] __kmalloc_cache_noprof+0x296/0x3d0 mm/slub.c:4367 kmalloc_noprof include/linux/slab.h:905 [inline] batadv_hash_new+0x57/0x290 net/batman-adv/hash.c:48 batadv_bla_init+0x511/0x7b0 net/batman-adv/bridge_loop_avoidance.c:1567 batadv_mesh_init+0x3dc/0x700 net/batman-adv/main.c:212 batadv_meshif_init_late+0xa3a/0xee0 net/batman-adv/mesh-interface.c:826 register_netdevice+0x6bc/0x1af0 net/core/dev.c:10936 rtnl_newlink_create+0x305/0xaf0 net/core/rtnetlink.c:3833 __rtnl_newlink net/core/rtnetlink.c:3950 [inline] rtnl_newlink+0x16d6/0x1c70 net/core/rtnetlink.c:4065 rtnetlink_rcv_msg+0x7cc/0xb70 net/core/rtnetlink.c:6955 netlink_rcv_skb+0x219/0x490 net/netlink/af_netlink.c:2534 page last free pid 5851 tgid 5851 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1262 [inline] __free_frozen_pages+0xb05/0xcd0 mm/page_alloc.c:2725 discard_slab mm/slub.c:2730 [inline] __put_partials+0x161/0x1c0 mm/slub.c:3199 put_cpu_partial+0x17c/0x250 mm/slub.c:3274 __slab_free+0x2f7/0x400 mm/slub.c:4526 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4161 [inline] slab_alloc_node mm/slub.c:4210 [inline] kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4217 anon_vma_chain_alloc mm/rmap.c:142 [inline] __anon_vma_prepare+0xcb/0x4a0 mm/rmap.c:195 __vmf_anon_prepare mm/memory.c:3432 [inline] vmf_anon_prepare mm/internal.h:415 [inline] do_anonymous_page mm/memory.c:4996 [inline] do_pte_missing mm/memory.c:4158 [inline] handle_pte_fault mm/memory.c:5997 [inline] __handle_mm_fault+0x4b7d/0x5380 mm/memory.c:6140 handle_mm_fault+0x2d5/0x7f0 mm/memory.c:6309 do_user_addr_fault+0xa81/0x1390 arch/x86/mm/fault.c:1337 handle_page_fault arch/x86/mm/fault.c:1480 [inline] exc_page_fault+0x68/0x110 arch/x86/mm/fault.c:1538 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 Memory state around the buggy address: ffff88807a3bd880: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc ffff88807a3bd900: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc >ffff88807a3bd980: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc ^ ffff88807a3bda00: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc ffff88807a3bda80: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc ==================================================================