public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
* [PATCH] KMSAN: uninit-value in n_tty_receive_buf_closing
@ 2025-09-25  8:41 Pei Xiao
  2025-09-25 10:09 ` [syzbot] [serial?] KMSAN: uninit-value in n_tty_receive_buf_closing (3) syzbot
  0 siblings, 1 reply; 4+ messages in thread
From: Pei Xiao @ 2025-09-25  8:41 UTC (permalink / raw)
  To: syzbot+62edf7e27b2e8f754525; +Cc: linux-kernel, syzkaller-bugs, Pei Xiao

#syz test
---
 drivers/tty/tty_buffer.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 67271fc0b223..62d32556a24b 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -108,6 +108,7 @@ static void tty_buffer_reset(struct tty_buffer *p, size_t size)
 	p->lookahead = 0;
 	p->read = 0;
 	p->flags = true;
+	memset(p->data, 0, size);
 }
 
 /**
@@ -177,7 +178,7 @@ static struct tty_buffer *tty_buffer_alloc(struct tty_port *port, size_t size)
 	 */
 	if (atomic_read(&port->buf.mem_used) > port->buf.mem_limit)
 		return NULL;
-	p = kmalloc(struct_size(p, data, 2 * size), GFP_ATOMIC | __GFP_NOWARN);
+	p = kzalloc(struct_size(p, data, 2 * size), GFP_ATOMIC | __GFP_NOWARN);
 	if (p == NULL)
 		return NULL;
 
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread
* [syzbot] [serial?] KMSAN: uninit-value in n_tty_receive_buf_closing (3)
@ 2024-08-19 13:42 syzbot
  2024-12-27 18:44 ` syzbot
  0 siblings, 1 reply; 4+ messages in thread
From: syzbot @ 2024-08-19 13:42 UTC (permalink / raw)
  To: gregkh, jirislaby, linux-kernel, linux-serial, syzkaller-bugs

Hello,

syzbot found the following issue on:

HEAD commit:    1fb918967b56 Merge tag 'for-6.11-rc3-tag' of git://git.ker..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10383409980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=836be0e882e376f7
dashboard link: https://syzkaller.appspot.com/bug?extid=dd514b5f0cf048aec256
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: i386

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c4ce70611394/disk-1fb91896.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/014bed8fa88a/vmlinux-1fb91896.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f8aa322233dc/bzImage-1fb91896.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+dd514b5f0cf048aec256@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in n_tty_receive_char_closing drivers/tty/n_tty.c:1454 [inline]
BUG: KMSAN: uninit-value in n_tty_receive_buf_closing+0x539/0xb40 drivers/tty/n_tty.c:1567
 n_tty_receive_char_closing drivers/tty/n_tty.c:1454 [inline]
 n_tty_receive_buf_closing+0x539/0xb40 drivers/tty/n_tty.c:1567
 __receive_buf drivers/tty/n_tty.c:1630 [inline]
 n_tty_receive_buf_common+0x196b/0x2490 drivers/tty/n_tty.c:1739
 n_tty_receive_buf2+0x4c/0x60 drivers/tty/n_tty.c:1785
 tty_ldisc_receive_buf+0xd0/0x290 drivers/tty/tty_buffer.c:387
 tty_port_default_receive_buf+0xdf/0x190 drivers/tty/tty_port.c:37
 receive_buf drivers/tty/tty_buffer.c:445 [inline]
 flush_to_ldisc+0x473/0xdb0 drivers/tty/tty_buffer.c:495
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0xae0/0x1c40 kernel/workqueue.c:3312
 worker_thread+0xea5/0x1520 kernel/workqueue.c:3390
 kthread+0x3dd/0x540 kernel/kthread.c:389
 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:3994 [inline]
 slab_alloc_node mm/slub.c:4037 [inline]
 __do_kmalloc_node mm/slub.c:4157 [inline]
 __kmalloc_noprof+0x661/0xf30 mm/slub.c:4170
 kmalloc_noprof include/linux/slab.h:685 [inline]
 tty_buffer_alloc drivers/tty/tty_buffer.c:180 [inline]
 __tty_buffer_request_room+0x36e/0x6d0 drivers/tty/tty_buffer.c:273
 __tty_insert_flip_string_flags+0x140/0x570 drivers/tty/tty_buffer.c:309
 tty_insert_flip_char include/linux/tty_flip.h:77 [inline]
 uart_insert_char+0x39e/0xa10 drivers/tty/serial/serial_core.c:3568
 serial8250_read_char+0x1a7/0x5d0 drivers/tty/serial/8250/8250_port.c:1743
 serial8250_rx_chars drivers/tty/serial/8250/8250_port.c:1760 [inline]
 serial8250_handle_irq+0x77a/0xb80 drivers/tty/serial/8250/8250_port.c:1924
 serial8250_default_handle_irq+0x120/0x2b0 drivers/tty/serial/8250/8250_port.c:1949
 serial8250_interrupt+0xc5/0x360 drivers/tty/serial/8250/8250_core.c:86
 __handle_irq_event_percpu+0x118/0xca0 kernel/irq/handle.c:158
 handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
 handle_irq_event+0xef/0x2c0 kernel/irq/handle.c:210
 handle_edge_irq+0x340/0xfb0 kernel/irq/chip.c:831
 generic_handle_irq_desc include/linux/irqdesc.h:173 [inline]
 handle_irq arch/x86/kernel/irq.c:247 [inline]
 call_irq_handler arch/x86/kernel/irq.c:259 [inline]
 __common_interrupt+0x97/0x1f0 arch/x86/kernel/irq.c:285
 common_interrupt+0x8f/0xa0 arch/x86/kernel/irq.c:278
 asm_common_interrupt+0x2b/0x40 arch/x86/include/asm/idtentry.h:693

CPU: 1 UID: 0 PID: 3148 Comm: kworker/u8:16 Not tainted 6.11.0-rc3-syzkaller-00066-g1fb918967b56 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
Workqueue: events_unbound flush_to_ldisc
=====================================================


---
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@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2025-09-25 10:09 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
     [not found] <CABPJ0viXDF2o1MjbsUBC=0aaBx+CxArAr5rkt961TrVibqLLPQ@mail.gmail.com>
2025-09-25  6:37 ` [syzbot] [serial?] KMSAN: uninit-value in n_tty_receive_buf_closing (3) syzbot
2025-09-25  8:41 [PATCH] KMSAN: uninit-value in n_tty_receive_buf_closing Pei Xiao
2025-09-25 10:09 ` [syzbot] [serial?] KMSAN: uninit-value in n_tty_receive_buf_closing (3) syzbot
  -- strict thread matches above, loose matches on Subject: below --
2024-08-19 13:42 syzbot
2024-12-27 18:44 ` syzbot

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox