syzbot


KMSAN: uninit-value in pctv452e_i2c_msg

Status: upstream: reported on 2025/10/10 04:19
Subsystems: media
[Documentation on labels]
Reported-by: syzbot+480edd2cadb85ddb4bbe@syzkaller.appspotmail.com
First crash: 6d13h, last: 5d23h
Discussions (2)
Title Replies (including bot) Last reply
[PATCH] meida: dvb-usb: Optimizing err() output 1 (1) 2025/10/10 15:21
[syzbot] [media?] KMSAN: uninit-value in pctv452e_i2c_msg 0 (1) 2025/10/10 04:19

Sample crash report:
=====================================================
BUG: KMSAN: uninit-value in hex_string+0x681/0x740 lib/vsprintf.c:1220
 hex_string+0x681/0x740 lib/vsprintf.c:1220
 pointer+0x2c7/0x1bd0 lib/vsprintf.c:2520
 vsnprintf+0xf8a/0x1bd0 lib/vsprintf.c:2930
 vscnprintf+0x6d/0x120 lib/vsprintf.c:2991
 printk_sprint+0x53/0x5c0 kernel/printk/printk.c:2189
 vprintk_store+0xbb9/0x1530 kernel/printk/printk.c:2309
 vprintk_emit+0x21a/0xb60 kernel/printk/printk.c:2399
 vprintk_default+0x3f/0x50 kernel/printk/printk.c:2438
 vprintk+0x36/0x50 kernel/printk/printk_safe.c:82
 _printk+0x17e/0x1b0 kernel/printk/printk.c:2448
 pctv452e_i2c_msg+0x82a/0x8f0 drivers/media/usb/dvb-usb/pctv452e.c:467
 pctv452e_i2c_xfer+0x2e6/0x4c0 drivers/media/usb/dvb-usb/pctv452e.c:502
 __i2c_transfer+0xecd/0x3110 drivers/i2c/i2c-core-base.c:-1
 i2c_transfer+0x300/0x4b0 drivers/i2c/i2c-core-base.c:2317
 i2c_transfer_buffer_flags+0x138/0x200 drivers/i2c/i2c-core-base.c:2345
 i2c_master_recv include/linux/i2c.h:79 [inline]
 i2cdev_read+0x1b2/0x3c0 drivers/i2c/i2c-dev.c:155
 vfs_read+0x27c/0xf90 fs/read_write.c:570
 ksys_pread64 fs/read_write.c:763 [inline]
 __do_sys_pread64 fs/read_write.c:771 [inline]
 __se_sys_pread64 fs/read_write.c:768 [inline]
 __x64_sys_pread64+0x2ab/0x3b0 fs/read_write.c:768
 x64_sys_call+0x3370/0x3e30 arch/x86/include/generated/asm/syscalls_64.h:18
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4953 [inline]
 slab_alloc_node mm/slub.c:5245 [inline]
 __kmalloc_cache_noprof+0x8f5/0x16b0 mm/slub.c:5719
 kmalloc_noprof include/linux/slab.h:957 [inline]
 pctv452e_i2c_msg+0x98/0x8f0 drivers/media/usb/dvb-usb/pctv452e.c:425
 pctv452e_i2c_xfer+0x2e6/0x4c0 drivers/media/usb/dvb-usb/pctv452e.c:502
 __i2c_transfer+0xecd/0x3110 drivers/i2c/i2c-core-base.c:-1
 i2c_transfer+0x300/0x4b0 drivers/i2c/i2c-core-base.c:2317
 i2c_transfer_buffer_flags+0x138/0x200 drivers/i2c/i2c-core-base.c:2345
 i2c_master_recv include/linux/i2c.h:79 [inline]
 i2cdev_read+0x1b2/0x3c0 drivers/i2c/i2c-dev.c:155
 vfs_read+0x27c/0xf90 fs/read_write.c:570
 ksys_pread64 fs/read_write.c:763 [inline]
 __do_sys_pread64 fs/read_write.c:771 [inline]
 __se_sys_pread64 fs/read_write.c:768 [inline]
 __x64_sys_pread64+0x2ab/0x3b0 fs/read_write.c:768
 x64_sys_call+0x3370/0x3e30 arch/x86/include/generated/asm/syscalls_64.h:18
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 UID: 0 PID: 10013 Comm: syz.1.697 Not tainted syzkaller #0 PREEMPT(none) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
=====================================================

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/10/06 05:47 upstream 9b0d551bcc05 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in pctv452e_i2c_msg
2025/10/06 18:07 upstream 9b0d551bcc05 91305dbe .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in pctv452e_i2c_msg
2025/10/06 09:05 upstream 9b0d551bcc05 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in pctv452e_i2c_msg
2025/10/06 04:08 upstream 9b0d551bcc05 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in pctv452e_i2c_msg
* Struck through repros no longer work on HEAD.