syzbot

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BUG: KMSAN: kernel-infoleak in copy_to_user include/linux/uaccess.h:184 [inline]
BUG: KMSAN: kernel-infoleak in tty_copy_to_user drivers/tty/n_tty.c:171 [inline]
BUG: KMSAN: kernel-infoleak in canon_copy_from_read_buf drivers/tty/n_tty.c:2037 [inline]
BUG: KMSAN: kernel-infoleak in n_tty_read+0x24b2/0x2f70 drivers/tty/n_tty.c:2210
CPU: 1 PID: 9075 Comm: syz-executor6 Not tainted 4.17.0+ #22
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+0x185/0x1d0 lib/dump_stack.c:113
 kmsan_report+0x188/0x2a0 mm/kmsan/kmsan.c:990
 kmsan_internal_check_memory+0x17e/0x1f0 mm/kmsan/kmsan.c:1054
 kmsan_copy_to_user+0x73/0xb0 mm/kmsan/kmsan_hooks.c:479
 copy_to_user include/linux/uaccess.h:184 [inline]
 tty_copy_to_user drivers/tty/n_tty.c:171 [inline]
 canon_copy_from_read_buf drivers/tty/n_tty.c:2037 [inline]
 n_tty_read+0x24b2/0x2f70 drivers/tty/n_tty.c:2210
 tty_read+0x26e/0x6c0 drivers/tty/tty_io.c:865
 __vfs_read+0x1b2/0x9d0 fs/read_write.c:416
 vfs_read+0x36c/0x6b0 fs/read_write.c:452
 ksys_read fs/read_write.c:578 [inline]
 __do_sys_read fs/read_write.c:588 [inline]
 __se_sys_read fs/read_write.c:586 [inline]
 __x64_sys_read+0x1bf/0x3e0 fs/read_write.c:586
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x455e29
RSP: 002b:00007f6e2a996c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f6e2a9976d4 RCX: 0000000000455e29
RDX: 00000000ffffff5c RSI: 0000000020000080 RDI: 0000000000000016
RBP: 000000000072bf48 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004c03b4 R14: 00000000004d0f40 R15: 0000000000000001

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:256 [inline]
 kmsan_internal_alloc_meta_for_pages+0x146/0x700 mm/kmsan/kmsan.c:702
 kmsan_alloc_page+0x75/0xd0 mm/kmsan/kmsan_hooks.c:250
 __alloc_pages_nodemask+0xf7b/0x5cc0 mm/page_alloc.c:4404
 alloc_pages_current+0x6b1/0x970 mm/mempolicy.c:2093
 alloc_pages include/linux/gfp.h:494 [inline]
 __vmalloc_area_node mm/vmalloc.c:1702 [inline]
 __vmalloc_node_range+0x8bf/0x1170 mm/vmalloc.c:1767
 __vmalloc_node mm/vmalloc.c:1812 [inline]
 __vmalloc_node_flags mm/vmalloc.c:1826 [inline]
 vmalloc+0xd8/0xf0 mm/vmalloc.c:1848
 n_tty_open+0x4a/0x490 drivers/tty/n_tty.c:1881
 tty_ldisc_open drivers/tty/tty_ldisc.c:466 [inline]
 tty_ldisc_setup+0x375/0x670 drivers/tty/tty_ldisc.c:776
 tty_init_dev+0xb82/0x1020 drivers/tty/tty_io.c:1345
 ptmx_open+0x2bb/0x7c0 drivers/tty/pty.c:832
 chrdev_open+0xc25/0xd90 fs/char_dev.c:417
 do_dentry_open+0xccc/0x1440 fs/open.c:794
 vfs_open+0x1b6/0x2f0 fs/open.c:908
 do_last fs/namei.c:3365 [inline]
 path_openat+0x4771/0x6640 fs/namei.c:3506
 do_filp_open+0x261/0x640 fs/namei.c:3540
 do_sys_open+0x624/0x960 fs/open.c:1101
 __do_sys_openat fs/open.c:1128 [inline]
 __se_sys_openat fs/open.c:1122 [inline]
 __x64_sys_openat+0x129/0x170 fs/open.c:1122
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x63/0xe7

Byte 4094 of 4095 is uninitialized
Memory access starts at ffffc900018b305e
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