================================================================== BUG: KASAN: use-after-free in string_nocheck lib/vsprintf.c:643 [inline] BUG: KASAN: use-after-free in string+0x20f/0x2a0 lib/vsprintf.c:725 Read of size 1 at addr ffff88810aeed1b8 by task syz.0.2346/10393 CPU: 0 PID: 10393 Comm: syz.0.2346 Tainted: G W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: __dump_stack+0x21/0x24 lib/dump_stack.c:88 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106 print_address_description+0x71/0x200 mm/kasan/report.c:316 print_report+0x4a/0x60 mm/kasan/report.c:420 kasan_report+0x122/0x150 mm/kasan/report.c:524 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report_generic.c:348 string_nocheck lib/vsprintf.c:643 [inline] string+0x20f/0x2a0 lib/vsprintf.c:725 vsnprintf+0xec5/0x1990 lib/vsprintf.c:2805 seq_vprintf fs/seq_file.c:391 [inline] seq_printf+0x185/0x280 fs/seq_file.c:406 show_interrupts+0x8f9/0xa00 kernel/irq/proc.c:527 traverse+0x215/0x5e0 fs/seq_file.c:111 seq_read_iter+0xc68/0xd80 fs/seq_file.c:195 proc_reg_read_iter+0x1e0/0x2b0 fs/proc/inode.c:305 call_read_iter include/linux/fs.h:2276 [inline] generic_file_splice_read+0x1d9/0x530 fs/splice.c:308 do_splice_to fs/splice.c:792 [inline] splice_direct_to_actor+0x3d0/0xb30 fs/splice.c:864 do_splice_direct+0x1c2/0x2d0 fs/splice.c:973 do_sendfile+0x515/0xe20 fs/read_write.c:1255 __do_sys_sendfile64 fs/read_write.c:1317 [inline] __se_sys_sendfile64 fs/read_write.c:1309 [inline] __x64_sys_sendfile64+0x146/0x1f0 fs/read_write.c:1309 x64_sys_call+0x62c/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:41 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f105f99e159 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f1060867028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f105fc26180 RCX: 00007f105f99e159 RDX: 0000200000000080 RSI: 0000000000000004 RDI: 0000000000000005 RBP: 00007f105fa3506b R08: 0000000000000000 R09: 0000000000000000 R10: 00000000000007ff R11: 0000000000000246 R12: 0000000000000000 R13: 00007f105fc26218 R14: 00007f105fc26180 R15: 00007ffe73ab6b38 Allocated by task 1: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 kasan_save_alloc_info+0x1f/0x30 mm/kasan/generic.c:505 ____kasan_kmalloc mm/kasan/common.c:380 [inline] __kasan_kmalloc+0x95/0xb0 mm/kasan/common.c:389 kasan_kmalloc include/linux/kasan.h:212 [inline] __do_kmalloc_node mm/slab_common.c:938 [inline] __kmalloc_node_track_caller+0xb1/0x1e0 mm/slab_common.c:958 kvasprintf+0xe8/0x1a0 lib/kasprintf.c:25 kasprintf+0xdf/0x130 lib/kasprintf.c:59 uart_add_one_port+0x38b/0x1cf0 drivers/tty/serial/serial_core.c:3117 serial8250_register_8250_port+0x1368/0x1b70 drivers/tty/serial/8250/8250_core.c:1092 serial_pnp_probe+0x51e/0x710 drivers/tty/serial/8250/8250_pnp.c:478 pnp_device_probe+0x312/0x4d0 drivers/pnp/driver.c:111 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x2d7/0x9a0 drivers/base/dd.c:639 __driver_probe_device+0x193/0x270 drivers/base/dd.c:808 driver_probe_device+0x54/0x3e0 drivers/base/dd.c:838 __driver_attach+0x41a/0x5d0 drivers/base/dd.c:1224 bus_for_each_dev+0x18c/0x200 drivers/base/bus.c:303 driver_attach+0x42/0x50 drivers/base/dd.c:1241 bus_add_driver+0x322/0x560 drivers/base/bus.c:620 driver_register+0x335/0x440 drivers/base/driver.c:246 pnp_register_driver+0x7d/0x90 drivers/pnp/driver.c:273 serial8250_pnp_init+0x15/0x20 drivers/tty/serial/8250/8250_pnp.c:533 serial8250_init+0xa0/0x16e drivers/tty/serial/8250/8250_core.c:1191 do_one_initcall+0x1d6/0x580 init/main.c:1433 do_initcall_level+0x174/0x2df init/main.c:1506 do_initcalls+0x50/0x92 init/main.c:1522 do_basic_setup+0x92/0x99 init/main.c:1541 kernel_init_freeable+0x2d1/0x42d init/main.c:1761 kernel_init+0x1d/0x1c0 init/main.c:1649 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Freed by task 10363: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:516 ____kasan_slab_free+0x132/0x180 mm/kasan/common.c:242 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:250 kasan_slab_free include/linux/kasan.h:178 [inline] slab_free_hook mm/slub.c:1750 [inline] slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1776 slab_free mm/slub.c:3712 [inline] __kmem_cache_free+0xb7/0x1b0 mm/slub.c:3728 kfree+0x6f/0xf0 mm/slab_common.c:990 uart_remove_one_port+0x36a/0x720 drivers/tty/serial/serial_core.c:3235 serial8250_unregister_port+0xad/0x250 drivers/tty/serial/8250/8250_core.c:1154 serial_pnp_remove+0x6b/0x90 drivers/tty/serial/8250/8250_pnp.c:496 pnp_device_remove+0x84/0x260 drivers/pnp/driver.c:133 device_remove drivers/base/dd.c:548 [inline] __device_release_driver drivers/base/dd.c:1283 [inline] device_release_driver_internal+0x486/0x7e0 drivers/base/dd.c:1309 device_driver_detach+0x3b/0x40 drivers/base/dd.c:1345 unbind_store+0x2e5/0x300 drivers/base/bus.c:193 drv_attr_store+0x88/0xb0 drivers/base/bus.c:77 sysfs_kf_write+0x137/0x150 fs/sysfs/file.c:136 kernfs_fop_write_iter+0x307/0x470 fs/kernfs/file.c:352 call_write_iter include/linux/fs.h:2282 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x5ef/0xd00 fs/read_write.c:584 ksys_write+0x14a/0x260 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __x64_sys_write+0x7b/0x90 fs/read_write.c:646 x64_sys_call+0x27b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:2 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 The buggy address belongs to the object at ffff88810aeed1b8 which belongs to the cache kmalloc-8 of size 8 The buggy address is located 0 bytes inside of 8-byte region [ffff88810aeed1b8, ffff88810aeed1c0) The buggy address belongs to the physical page: page:ffffea00042bbb40 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10aeed flags: 0x4000000000000200(slab|zone=1) raw: 4000000000000200 ffffea00043db500 dead000000000002 ffff888100042300 raw: 0000000000000000 0000000000660066 00000001ffffffff 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 1, tgid 1 (swapper/0), ts 1947102424, free_ts 0 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2673 prep_new_page+0x1c/0x110 mm/page_alloc.c:2680 get_page_from_freelist+0x2ca9/0x2d20 mm/page_alloc.c:4587 __alloc_pages+0x1fa/0x610 mm/page_alloc.c:5931 alloc_slab_page+0x6e/0xf0 include/linux/gfp.h:-1 allocate_slab mm/slub.c:1967 [inline] new_slab+0x98/0x3e0 mm/slub.c:2020 ___slab_alloc+0x70f/0xb70 mm/slub.c:3177 __slab_alloc+0x5e/0xa0 mm/slub.c:3263 slab_alloc_node mm/slub.c:3348 [inline] __kmem_cache_alloc_node+0x204/0x2d0 mm/slub.c:3423 __do_kmalloc_node mm/slab_common.c:937 [inline] __kmalloc_node_track_caller+0xa1/0x1e0 mm/slab_common.c:958 kstrdup mm/util.c:66 [inline] kstrdup_const+0x5a/0xa0 mm/util.c:89 __kernfs_new_node+0xa6/0x670 fs/kernfs/dir.c:610 kernfs_new_node+0x150/0x260 fs/kernfs/dir.c:690 kernfs_create_dir_ns+0x47/0x130 fs/kernfs/dir.c:1046 sysfs_create_dir_ns+0x128/0x290 fs/sysfs/dir.c:59 create_dir lib/kobject.c:63 [inline] kobject_add_internal+0x718/0xc20 lib/kobject.c:231 page_owner free stack trace missing Memory state around the buggy address: ffff88810aeed080: fc fc fc fc fa fc fc fc fc 00 fc fc fc fc 00 fc ffff88810aeed100: fc fc fc 04 fc fc fc fc fa fc fc fc fc fa fc fc >ffff88810aeed180: fc fc 00 fc fc fc fc fa fc fc fc fc fa fc fc fc ^ ffff88810aeed200: fc fa fc fc fc fc fa fc fc fc fc 00 fc fc fc fc ffff88810aeed280: 00 fc fc fc fc fa fc fc fc fc 07 fc fc fc fc fa ==================================================================