================================================================== BUG: KASAN: slab-out-of-bounds in afs_split_string fs/afs/addr_prefs.c:51 [inline] BUG: KASAN: slab-out-of-bounds in afs_proc_addr_prefs_write+0x13a9/0x15f0 fs/afs/addr_prefs.c:415 Read of size 1 at addr ffff88804ec94aa7 by task syz.1.1296/13045 CPU: 1 UID: 0 PID: 13045 Comm: syz.1.1296 Tainted: G U 6.16.0-rc3-syzkaller-00329-gdfba48a70cb6 #0 PREEMPT(full) Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 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:408 [inline] print_report+0xcd/0x680 mm/kasan/report.c:521 kasan_report+0xe0/0x110 mm/kasan/report.c:634 afs_split_string fs/afs/addr_prefs.c:51 [inline] afs_proc_addr_prefs_write+0x13a9/0x15f0 fs/afs/addr_prefs.c:415 proc_simple_write+0x114/0x1b0 fs/proc/generic.c:825 pde_write fs/proc/inode.c:330 [inline] proc_reg_write+0x240/0x330 fs/proc/inode.c:342 do_loop_readv_writev fs/read_write.c:850 [inline] do_loop_readv_writev fs/read_write.c:835 [inline] vfs_writev+0x5df/0xde0 fs/read_write.c:1059 do_writev+0x132/0x340 fs/read_write.c:1103 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8f9538e929 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:00007f8f96148038 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 00007f8f955b6080 RCX: 00007f8f9538e929 RDX: 0000000000000003 RSI: 0000200000000080 RDI: 000000000000000c RBP: 00007f8f95410b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f8f955b6080 R15: 00007ffd0e7ae208 Allocated by task 13045: 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 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4328 [inline] __kmalloc_node_track_caller_noprof+0x221/0x510 mm/slub.c:4347 memdup_user_nul+0x2b/0x120 mm/util.c:302 proc_simple_write+0xc7/0x1b0 fs/proc/generic.c:822 pde_write fs/proc/inode.c:330 [inline] proc_reg_write+0x240/0x330 fs/proc/inode.c:342 do_loop_readv_writev fs/read_write.c:850 [inline] do_loop_readv_writev fs/read_write.c:835 [inline] vfs_writev+0x5df/0xde0 fs/read_write.c:1059 do_writev+0x132/0x340 fs/read_write.c:1103 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88804ec94aa0 which belongs to the cache kmalloc-8 of size 8 The buggy address is located 0 bytes to the right of allocated 7-byte region [ffff88804ec94aa0, ffff88804ec94aa7) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4ec94 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88801b841500 ffffea0000d307c0 dead000000000002 raw: 0000000000000000 0000000080800080 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 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 7379, tgid 7378 (syz.1.286), ts 192366948321, free_ts 192336969022 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1704 prep_new_page mm/page_alloc.c:1712 [inline] get_page_from_freelist+0x1321/0x3890 mm/page_alloc.c:3669 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:4959 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2419 alloc_slab_page mm/slub.c:2451 [inline] allocate_slab mm/slub.c:2619 [inline] new_slab+0x23b/0x330 mm/slub.c:2673 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3859 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3949 __slab_alloc_node mm/slub.c:4024 [inline] slab_alloc_node mm/slub.c:4185 [inline] __do_kmalloc_node mm/slub.c:4327 [inline] __kmalloc_node_track_caller_noprof+0x2ee/0x510 mm/slub.c:4347 kvasprintf+0xbc/0x160 lib/kasprintf.c:25 kvasprintf_const+0x66/0x1a0 lib/kasprintf.c:49 kobject_set_name_vargs+0x5a/0x140 lib/kobject.c:274 kobject_add_varg lib/kobject.c:368 [inline] kobject_init_and_add+0xe7/0x190 lib/kobject.c:457 netdev_queue_add_kobject net/core/net-sysfs.c:1976 [inline] netdev_queue_update_kobjects+0x32d/0x720 net/core/net-sysfs.c:2035 register_queue_kobjects net/core/net-sysfs.c:2098 [inline] netdev_register_kobject+0x28c/0x3a0 net/core/net-sysfs.c:2340 register_netdevice+0x13dc/0x2270 net/core/dev.c:11105 __ip_tunnel_create+0x540/0x6e0 net/ipv4/ip_tunnel.c:268 page last free pid 7384 tgid 7378 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1248 [inline] __free_frozen_pages+0x7fe/0x1180 mm/page_alloc.c:2706 vfree+0x1fd/0xb50 mm/vmalloc.c:3426 vb2_vmalloc_put drivers/media/common/videobuf2/videobuf2-vmalloc.c:68 [inline] vb2_vmalloc_put+0x7b/0xc0 drivers/media/common/videobuf2/videobuf2-vmalloc.c:63 __vb2_buf_mem_free+0x15d/0x2d0 drivers/media/common/videobuf2/videobuf2-core.c:275 __vb2_free_mem drivers/media/common/videobuf2/videobuf2-core.c:571 [inline] __vb2_queue_free+0x7ee/0xa30 drivers/media/common/videobuf2/videobuf2-core.c:599 vb2_core_reqbufs+0x276/0xfe0 drivers/media/common/videobuf2/videobuf2-core.c:911 __vb2_cleanup_fileio+0xed/0x190 drivers/media/common/videobuf2/videobuf2-core.c:2993 vb2_core_queue_release+0x1f/0x190 drivers/media/common/videobuf2/videobuf2-core.c:2692 vb2_queue_release drivers/media/common/videobuf2/videobuf2-v4l2.c:956 [inline] _vb2_fop_release+0xe8/0x280 drivers/media/common/videobuf2/videobuf2-v4l2.c:1158 vivid_fop_release+0x155/0xc40 drivers/media/test-drivers/vivid/vivid-core.c:667 v4l2_release+0x232/0x460 drivers/media/v4l2-core/v4l2-dev.c:458 __fput+0x3ff/0xb70 fs/file_table.c:465 task_work_run+0x14d/0x240 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:114 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline] do_syscall_64+0x3f6/0x490 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88804ec94980: fa fc fc fc fa fc fc fc fa fc fc fc fa fc fc fc ffff88804ec94a00: fa fc fc fc fa fc fc fc 00 fc fc fc fa fc fc fc >ffff88804ec94a80: 04 fc fc fc 07 fc fc fc fa fc fc fc fa fc fc fc ^ ffff88804ec94b00: 05 fc fc fc fa fc fc fc fa fc fc fc fa fc fc fc ffff88804ec94b80: 06 fc fc fc fa fc fc fc fa fc fc fc 05 fc fc fc ==================================================================