================================================================== BUG: KASAN: slab-use-after-free in v9fs_stat2inode_dotl+0xb3f/0xce0 fs/9p/vfs_inode_dotl.c:569 Read of size 8 at addr ffff8880195c9500 by task syz-executor.0/6280 CPU: 1 PID: 6280 Comm: syz-executor.0 Not tainted 6.9.0-rc1-syzkaller-00021-g962490525cff #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 print_address_description mm/kasan/report.c:377 [inline] print_report+0xc3/0x620 mm/kasan/report.c:488 kasan_report+0xd9/0x110 mm/kasan/report.c:601 v9fs_stat2inode_dotl+0xb3f/0xce0 fs/9p/vfs_inode_dotl.c:569 v9fs_fid_iget_dotl+0x1cb/0x260 fs/9p/vfs_inode_dotl.c:85 v9fs_get_inode_from_fid fs/9p/v9fs.h:230 [inline] v9fs_mount+0x515/0xa90 fs/9p/vfs_super.c:142 legacy_get_tree+0x109/0x220 fs/fs_context.c:662 vfs_get_tree+0x8f/0x380 fs/super.c:1797 do_new_mount fs/namespace.c:3352 [inline] path_mount+0x6e1/0x1f10 fs/namespace.c:3679 do_mount fs/namespace.c:3692 [inline] __do_sys_mount fs/namespace.c:3898 [inline] __se_sys_mount fs/namespace.c:3875 [inline] __ia32_sys_mount+0x295/0x320 fs/namespace.c:3875 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x7a/0x120 arch/x86/entry/common.c:321 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:346 entry_SYSENTER_compat_after_hwframe+0x7a/0x84 RIP: 0023:0xf7297579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f5e915ac EFLAGS: 00000292 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 0000000020000080 RCX: 0000000020000040 RDX: 0000000020000100 RSI: 0000000000000000 RDI: 00000000200000c0 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 6280: 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:370 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:387 kmalloc include/linux/slab.h:628 [inline] p9_client_getattr_dotl+0x4c/0x1e0 net/9p/client.c:1726 v9fs_fid_iget_dotl+0xe7/0x260 fs/9p/vfs_inode_dotl.c:73 v9fs_get_inode_from_fid fs/9p/v9fs.h:230 [inline] v9fs_mount+0x515/0xa90 fs/9p/vfs_super.c:142 legacy_get_tree+0x109/0x220 fs/fs_context.c:662 vfs_get_tree+0x8f/0x380 fs/super.c:1797 do_new_mount fs/namespace.c:3352 [inline] path_mount+0x6e1/0x1f10 fs/namespace.c:3679 do_mount fs/namespace.c:3692 [inline] __do_sys_mount fs/namespace.c:3898 [inline] __se_sys_mount fs/namespace.c:3875 [inline] __ia32_sys_mount+0x295/0x320 fs/namespace.c:3875 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x7a/0x120 arch/x86/entry/common.c:321 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:346 entry_SYSENTER_compat_after_hwframe+0x7a/0x84 Freed by task 6280: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579 poison_slab_object mm/kasan/common.c:240 [inline] __kasan_slab_free+0x11d/0x1a0 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2106 [inline] slab_free mm/slub.c:4280 [inline] kfree+0x129/0x390 mm/slub.c:4390 v9fs_fid_iget_dotl+0x195/0x260 fs/9p/vfs_inode_dotl.c:81 v9fs_get_inode_from_fid fs/9p/v9fs.h:230 [inline] v9fs_mount+0x515/0xa90 fs/9p/vfs_super.c:142 legacy_get_tree+0x109/0x220 fs/fs_context.c:662 vfs_get_tree+0x8f/0x380 fs/super.c:1797 do_new_mount fs/namespace.c:3352 [inline] path_mount+0x6e1/0x1f10 fs/namespace.c:3679 do_mount fs/namespace.c:3692 [inline] __do_sys_mount fs/namespace.c:3898 [inline] __se_sys_mount fs/namespace.c:3875 [inline] __ia32_sys_mount+0x295/0x320 fs/namespace.c:3875 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x7a/0x120 arch/x86/entry/common.c:321 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:346 entry_SYSENTER_compat_after_hwframe+0x7a/0x84 The buggy address belongs to the object at ffff8880195c9500 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 0 bytes inside of freed 192-byte region [ffff8880195c9500, ffff8880195c95c0) The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x195c9 flags: 0xfff80000000800(slab|node=0|zone=1|lastcpupid=0xfff) page_type: 0xffffffff() raw: 00fff80000000800 ffff888014c42a00 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000100010 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 7393832043, free_ts 7377310619 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x2d4/0x350 mm/page_alloc.c:1534 prep_new_page mm/page_alloc.c:1541 [inline] get_page_from_freelist+0xa28/0x3780 mm/page_alloc.c:3317 __alloc_pages+0x22b/0x2460 mm/page_alloc.c:4575 __alloc_pages_node include/linux/gfp.h:238 [inline] alloc_pages_node include/linux/gfp.h:261 [inline] alloc_slab_page mm/slub.c:2175 [inline] allocate_slab mm/slub.c:2338 [inline] new_slab+0xcc/0x3a0 mm/slub.c:2391 ___slab_alloc+0x670/0x16d0 mm/slub.c:3525 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3610 __slab_alloc_node mm/slub.c:3663 [inline] slab_alloc_node mm/slub.c:3835 [inline] kmalloc_trace+0x2fb/0x330 mm/slub.c:3992 kmalloc include/linux/slab.h:628 [inline] kzalloc include/linux/slab.h:749 [inline] call_usermodehelper_setup+0x9a/0x340 kernel/umh.c:363 kobject_uevent_env+0xdce/0x15f0 lib/kobject_uevent.c:613 tty_register_device_attr+0x4bc/0x7c0 drivers/tty/tty_io.c:3296 tty_register_device drivers/tty/tty_io.c:3210 [inline] tty_register_driver+0x431/0x800 drivers/tty/tty_io.c:3473 legacy_pty_init drivers/tty/pty.c:579 [inline] pty_init+0x67c/0x1110 drivers/tty/pty.c:943 do_one_initcall+0x128/0x630 init/main.c:1238 do_initcall_level init/main.c:1300 [inline] do_initcalls init/main.c:1316 [inline] do_basic_setup init/main.c:1335 [inline] kernel_init_freeable+0x660/0xc50 init/main.c:1548 kernel_init+0x1c/0x2b0 init/main.c:1437 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 page last free pid 8 tgid 8 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1141 [inline] free_unref_page_prepare+0x527/0xb10 mm/page_alloc.c:2347 free_unref_page+0x33/0x3c0 mm/page_alloc.c:2487 vfree+0x181/0x7a0 mm/vmalloc.c:3324 delayed_vfree_work+0x56/0x70 mm/vmalloc.c:3245 process_one_work+0x902/0x1a30 kernel/workqueue.c:3254 process_scheduled_works kernel/workqueue.c:3335 [inline] worker_thread+0x6c8/0xf70 kernel/workqueue.c:3416 kthread+0x2c1/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243 Memory state around the buggy address: ffff8880195c9400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880195c9480: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880195c9500: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880195c9580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff8880195c9600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi