Hello, syzbot found the following issue on: HEAD commit: ff1ffd71d5f0 Merge tag 'hyperv-fixes-signed-20210915' of g.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1460b72d300000 kernel config: https://syzkaller.appspot.com/x/.config?x=6d93fe4341f98704 dashboard link: https://syzkaller.appspot.com/bug?extid=414020f76775cfa73bd5 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 userspace arch: i386 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+414020f76775cfa73bd5@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KASAN: slab-out-of-bounds in instrument_copy_to_user include/linux/instrumented.h:118 [inline] BUG: KASAN: slab-out-of-bounds in _copy_to_user lib/usercopy.c:32 [inline] BUG: KASAN: slab-out-of-bounds in _copy_to_user+0xc7/0x150 lib/usercopy.c:26 Read of size 16 at addr ffff88807df42418 by task syz-executor.4/4509 CPU: 0 PID: 4509 Comm: syz-executor.4 Not tainted 5.15.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0x6c/0x309 mm/kasan/report.c:256 __kasan_report mm/kasan/report.c:442 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:459 check_region_inline mm/kasan/generic.c:183 [inline] kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189 instrument_copy_to_user include/linux/instrumented.h:118 [inline] _copy_to_user lib/usercopy.c:32 [inline] _copy_to_user+0xc7/0x150 lib/usercopy.c:26 copy_to_user include/linux/uaccess.h:200 [inline] v4l2_compat_put_array_args+0x480/0x830 drivers/media/v4l2-core/v4l2-compat-ioctl32.c:1152 video_usercopy+0xc65/0x16b0 drivers/media/v4l2-core/v4l2-ioctl.c:3317 v4l2_ioctl+0x1b3/0x250 drivers/media/v4l2-core/v4l2-dev.c:364 v4l2_compat_ioctl32+0x216/0x2c0 drivers/media/v4l2-core/v4l2-compat-ioctl32.c:1251 __do_compat_sys_ioctl+0x1c7/0x290 fs/ioctl.c:972 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c RIP: 0023:0xf6f5a549 Code: 03 74 c0 01 10 05 03 74 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 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:00000000f45545fc EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000c0cc5604 RDX: 0000000020000180 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 4509: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] ____kasan_kmalloc mm/kasan/common.c:513 [inline] ____kasan_kmalloc mm/kasan/common.c:472 [inline] __kasan_kmalloc+0xa4/0xd0 mm/kasan/common.c:522 kmalloc_node include/linux/slab.h:614 [inline] kvmalloc_node+0x61/0x120 mm/util.c:587 kvmalloc include/linux/mm.h:805 [inline] video_usercopy+0x72b/0x16b0 drivers/media/v4l2-core/v4l2-ioctl.c:3281 v4l2_ioctl+0x1b3/0x250 drivers/media/v4l2-core/v4l2-dev.c:364 v4l2_compat_ioctl32+0x216/0x2c0 drivers/media/v4l2-core/v4l2-compat-ioctl32.c:1251 __do_compat_sys_ioctl+0x1c7/0x290 fs/ioctl.c:972 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c The buggy address belongs to the object at ffff88807df42400 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 24 bytes inside of 32-byte region [ffff88807df42400, ffff88807df42420) The buggy address belongs to the page: page:ffffea0001f7d080 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88807df429c0 pfn:0x7df42 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea000079e580 0000000f0000000f ffff888010c41500 raw: ffff88807df429c0 000000008040002f 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, ts 17452416960, free_ts 13762209776 prep_new_page mm/page_alloc.c:2424 [inline] get_page_from_freelist+0xa72/0x2f80 mm/page_alloc.c:4153 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5375 alloc_pages+0x1a7/0x300 mm/mempolicy.c:2197 alloc_slab_page mm/slub.c:1763 [inline] allocate_slab mm/slub.c:1900 [inline] new_slab+0x319/0x490 mm/slub.c:1963 ___slab_alloc+0x921/0xfe0 mm/slub.c:2994 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3081 slab_alloc_node mm/slub.c:3172 [inline] slab_alloc mm/slub.c:3214 [inline] __kmalloc_track_caller+0x2f1/0x310 mm/slub.c:4905 kstrdup+0x36/0x70 mm/util.c:60 kstrdup_const+0x53/0x80 mm/util.c:83 __kernfs_new_node+0x9d/0x8b0 fs/kernfs/dir.c:581 kernfs_new_node fs/kernfs/dir.c:647 [inline] kernfs_create_dir_ns+0x9c/0x220 fs/kernfs/dir.c:984 kernfs_create_dir include/linux/kernfs.h:566 [inline] cgroup_create kernel/cgroup/cgroup.c:5307 [inline] cgroup_mkdir+0x43e/0x10f0 kernel/cgroup/cgroup.c:5440 kernfs_iop_mkdir+0x146/0x1d0 fs/kernfs/dir.c:1142 vfs_mkdir+0x1ce/0x3f0 fs/namei.c:3885 do_mkdirat+0x285/0x300 fs/namei.c:3911 __do_sys_mkdir fs/namei.c:3931 [inline] __se_sys_mkdir fs/namei.c:3929 [inline] __x64_sys_mkdir+0xf2/0x140 fs/namei.c:3929 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1338 [inline] free_pcp_prepare+0x2c5/0x780 mm/page_alloc.c:1389 free_unref_page_prepare mm/page_alloc.c:3315 [inline] free_unref_page+0x19/0x690 mm/page_alloc.c:3394 free_contig_range+0xa8/0xf0 mm/page_alloc.c:9254 destroy_args+0xa8/0x646 mm/debug_vm_pgtable.c:1016 debug_vm_pgtable+0x295b/0x29ed mm/debug_vm_pgtable.c:1329 do_one_initcall+0x103/0x650 init/main.c:1303 do_initcall_level init/main.c:1376 [inline] do_initcalls init/main.c:1392 [inline] do_basic_setup init/main.c:1411 [inline] kernel_init_freeable+0x6b1/0x73a init/main.c:1614 kernel_init+0x1a/0x1d0 init/main.c:1505 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Memory state around the buggy address: ffff88807df42300: 00 00 00 fc fc fc fc fc fb fb fb fb fc fc fc fc ffff88807df42380: fa fb fb fb fc fc fc fc 00 00 00 fc fc fc fc fc >ffff88807df42400: 00 00 00 fc fc fc fc fc fa fb fb fb fc fc fc fc ^ ffff88807df42480: 00 00 00 fc fc fc fc fc 00 00 00 fc fc fc fc fc ffff88807df42500: 00 00 00 fc fc fc fc fc fa fb fb fb fc fc fc fc ================================================================== ---------------- Code disassembly (best guess): 0: 03 74 c0 01 add 0x1(%rax,%rax,8),%esi 4: 10 05 03 74 b8 01 adc %al,0x1b87403(%rip) # 0x1b8740d a: 10 06 adc %al,(%rsi) c: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 10: 10 07 adc %al,(%rdi) 12: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi 16: 10 08 adc %cl,(%rax) 18: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1c: 00 00 add %al,(%rax) 1e: 00 00 add %al,(%rax) 20: 00 51 52 add %dl,0x52(%rcx) 23: 55 push %rbp 24: 89 e5 mov %esp,%ebp 26: 0f 34 sysenter 28: cd 80 int $0x80 * 2a: 5d pop %rbp <-- trapping instruction 2b: 5a pop %rdx 2c: 59 pop %rcx 2d: c3 retq 2e: 90 nop 2f: 90 nop 30: 90 nop 31: 90 nop 32: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 39: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
