================================================================== 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 ffff888033352c07 by task syz.3.623/9442 CPU: 1 UID: 0 PID: 9442 Comm: syz.3.623 Tainted: G U 6.15.0-rc6-syzkaller-00105-g088d13246a46 #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+0xc3/0x670 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+0x117/0x1b0 fs/proc/generic.c:825 pde_write fs/proc/inode.c:330 [inline] proc_reg_write+0x23d/0x330 fs/proc/inode.c:342 do_loop_readv_writev fs/read_write.c:848 [inline] do_loop_readv_writev fs/read_write.c:833 [inline] vfs_writev+0x6c7/0xdc0 fs/read_write.c:1057 do_writev+0x132/0x330 fs/read_write.c:1101 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3ad998e969 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:00007f3ada8a9038 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 00007f3ad9bb6080 RCX: 00007f3ad998e969 RDX: 0000000000000003 RSI: 0000200000000080 RDI: 0000000000000003 RBP: 00007f3ad9a10ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f3ad9bb6080 R15: 00007ffc48228de8 Allocated by task 9442: 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:4327 [inline] __kmalloc_node_track_caller_noprof+0x221/0x510 mm/slub.c:4346 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+0x23d/0x330 fs/proc/inode.c:342 do_loop_readv_writev fs/read_write.c:848 [inline] do_loop_readv_writev fs/read_write.c:833 [inline] vfs_writev+0x6c7/0xdc0 fs/read_write.c:1057 do_writev+0x132/0x330 fs/read_write.c:1101 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888033352c00 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 [ffff888033352c00, ffff888033352c07) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x33352 anon flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88801b441500 0000000000000000 0000000000000001 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 9195, tgid 9190 (syz.3.577), ts 397180268937, free_ts 396822735738 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1718 prep_new_page mm/page_alloc.c:1726 [inline] get_page_from_freelist+0x135c/0x3920 mm/page_alloc.c:3688 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4970 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301 alloc_slab_page mm/slub.c:2450 [inline] allocate_slab mm/slub.c:2618 [inline] new_slab+0x244/0x340 mm/slub.c:2672 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3858 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3948 __slab_alloc_node mm/slub.c:4023 [inline] slab_alloc_node mm/slub.c:4184 [inline] __do_kmalloc_node mm/slub.c:4326 [inline] __kmalloc_node_track_caller_noprof+0x2ee/0x510 mm/slub.c:4346 __kmemdup_nul mm/util.c:63 [inline] kstrndup+0x6d/0x160 mm/util.c:119 bonding_sysfs_store_option+0x67/0x120 drivers/net/bonding/bond_sysfs.c:153 dev_attr_store+0x58/0x80 drivers/base/core.c:2440 sysfs_kf_write+0xef/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x354/0x510 fs/kernfs/file.c:334 do_iter_readv_writev+0x657/0x950 fs/read_write.c:825 vfs_writev+0x353/0xdc0 fs/read_write.c:1055 do_pwritev+0x1af/0x270 fs/read_write.c:1151 page last free pid 3017 tgid 3017 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1262 [inline] __free_frozen_pages+0x69d/0xff0 mm/page_alloc.c:2725 pagetable_free include/linux/mm.h:3019 [inline] pagetable_dtor_free include/linux/mm.h:3117 [inline] __tlb_remove_table include/asm-generic/tlb.h:215 [inline] __tlb_remove_table_free mm/mmu_gather.c:227 [inline] tlb_remove_table_rcu+0x116/0x1a0 mm/mmu_gather.c:290 rcu_do_batch kernel/rcu/tree.c:2568 [inline] rcu_core+0x79c/0x14e0 kernel/rcu/tree.c:2824 handle_softirqs+0x219/0x8e0 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] invoke_softirq kernel/softirq.c:453 [inline] __irq_exit_rcu+0x109/0x170 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+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 Memory state around the buggy address: ffff888033352b00: fa fc fc fc fa fc fc fc fa fc fc fc fa fc fc fc ffff888033352b80: fa fc fc fc fa fc fc fc fa fc fc fc fa fc fc fc >ffff888033352c00: 07 fc fc fc fa fc fc fc fa fc fc fc fa fc fc fc ^ ffff888033352c80: fa fc fc fc fa fc fc fc fa fc fc fc fa fc fc fc ffff888033352d00: fa fc fc fc fa fc fc fc fa fc fc fc fa fc fc fc ==================================================================