================================================================== BUG: KASAN: use-after-free in n_tty_check_throttle drivers/tty/n_tty.c:264 [inline] BUG: KASAN: use-after-free in n_tty_receive_buf_common+0x264d/0x2a50 drivers/tty/n_tty.c:1759 Read of size 1 at addr ffff888091969d3f by task syz-executor.2/26077 CPU: 0 PID: 26077 Comm: syz-executor.2 Not tainted 4.19.107-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x188/0x20d lib/dump_stack.c:118 print_address_description.cold+0x7c/0x212 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report mm/kasan/report.c:412 [inline] kasan_report.cold+0x88/0x2b9 mm/kasan/report.c:396 n_tty_check_throttle drivers/tty/n_tty.c:264 [inline] n_tty_receive_buf_common+0x264d/0x2a50 drivers/tty/n_tty.c:1759 tty_ldisc_receive_buf+0xa9/0x190 drivers/tty/tty_buffer.c:456 paste_selection+0x1d7/0x433 drivers/tty/vt/selection.c:366 tioclinux+0x12c/0x480 drivers/tty/vt/vt.c:3030 vt_ioctl+0x1811/0x2310 drivers/tty/vt/vt_ioctl.c:364 tty_ioctl+0x7a1/0x1420 drivers/tty/tty_io.c:2669 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xcda/0x12e0 fs/ioctl.c:688 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c479 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f97057fec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f97057ff6d4 RCX: 000000000045c479 RDX: 0000000020000100 RSI: 000000000000541c RDI: 0000000000000007 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000574 R14: 00000000004c7c8f R15: 000000000076bf2c Allocated by task 26070: set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc mm/kasan/kasan.c:553 [inline] kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:531 __do_kmalloc mm/slab.c:3727 [inline] __kmalloc+0x15b/0x770 mm/slab.c:3736 kmalloc_array include/linux/slab.h:637 [inline] set_selection+0x7d4/0x1200 drivers/tty/vt/selection.c:295 tioclinux+0x115/0x480 drivers/tty/vt/vt.c:3026 vt_ioctl+0x1811/0x2310 drivers/tty/vt/vt_ioctl.c:364 tty_ioctl+0x7a1/0x1420 drivers/tty/tty_io.c:2669 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xcda/0x12e0 fs/ioctl.c:688 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 26078: set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0xf7/0x140 mm/kasan/kasan.c:521 __cache_free mm/slab.c:3503 [inline] kfree+0xce/0x220 mm/slab.c:3822 set_selection+0x7f1/0x1200 drivers/tty/vt/selection.c:302 tioclinux+0x115/0x480 drivers/tty/vt/vt.c:3026 vt_ioctl+0x1811/0x2310 drivers/tty/vt/vt_ioctl.c:364 tty_ioctl+0x7a1/0x1420 drivers/tty/tty_io.c:2669 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xcda/0x12e0 fs/ioctl.c:688 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff888091969b40 which belongs to the cache kmalloc-8192 of size 8192 The buggy address is located 511 bytes inside of 8192-byte region [ffff888091969b40, ffff88809196bb40) The buggy address belongs to the page: page:ffffea0002465a00 count:1 mapcount:0 mapping:ffff88812c3d5080 index:0x0 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffffea000267c108 ffffea0000f5d508 ffff88812c3d5080 raw: 0000000000000000 ffff888091969b40 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888091969c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888091969c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888091969d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888091969d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888091969e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== kauditd_printk_skb: 264 callbacks suppressed audit: type=1400 audit(2000000160.149:71790): avc: denied { map } for pid=26521 comm="blkid" path="/sbin/blkid" dev="sda1" ino=16128 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(2000000160.149:71791): avc: denied { map } for pid=26518 comm="blkid" path="/lib/x86_64-linux-gnu/libc-2.13.so" dev="sda1" ino=2784 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(2000000160.149:71792): avc: denied { map } for pid=26518 comm="blkid" path="/lib/x86_64-linux-gnu/libc-2.13.so" dev="sda1" ino=2784 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(2000000160.149:71793): avc: denied { map } for pid=26518 comm="blkid" path="/lib/x86_64-linux-gnu/libuuid.so.1.3.0" dev="sda1" ino=2819 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(2000000160.149:71794): avc: denied { map } for pid=26518 comm="blkid" path="/lib/x86_64-linux-gnu/libuuid.so.1.3.0" dev="sda1" ino=2819 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(2000000160.179:71795): avc: denied { map } for pid=26521 comm="blkid" path="/lib/x86_64-linux-gnu/ld-2.13.so" dev="sda1" ino=2668 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(2000000160.179:71796): avc: denied { map } for pid=26521 comm="blkid" path="/lib/x86_64-linux-gnu/ld-2.13.so" dev="sda1" ino=2668 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(2000000160.179:71797): avc: denied { map } for pid=26521 comm="blkid" path="/etc/ld.so.cache" dev="sda1" ino=2251 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(2000000160.199:71798): avc: denied { map } for pid=26521 comm="blkid" path="/lib/x86_64-linux-gnu/libblkid.so.1.1.0" dev="sda1" ino=2825 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(2000000160.199:71799): avc: denied { map } for pid=26521 comm="blkid" path="/lib/x86_64-linux-gnu/libblkid.so.1.1.0" dev="sda1" ino=2825 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1