CVE-2026-23121

In the Linux kernel, the following vulnerability has been resolved:

mISDN: annotate data-race around dev->work

dev->work can re read locklessly in mISDN_read()

and mISDN_poll(). Add READ_ONCE()/WRITE_ONCE() annotations.

BUG: KCSAN: data-race in mISDN_ioctl / mISDN_read

write to 0xffff88812d848280 of 4 bytes by task 10864 on cpu 1:

misdn_add_timer drivers/isdn/mISDN/timerdev.c:175 [inline]

mISDN_ioctl+0x2fb/0x550 drivers/isdn/mISDN/timerdev.c:233

vfs_ioctl fs/ioctl.c:51 [inline]

__do_sys_ioctl fs/ioctl.c:597 [inline]

__se_sys_ioctl+0xce/0x140 fs/ioctl.c:583

__x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583

x64_sys_call+0x14b0/0x3000 arch/x86/include/generated/asm/syscalls_64.h:17

do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]

do_syscall_64+0xd8/0x2c0 arch/x86/entry/syscall_64.c:94

entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88812d848280 of 4 bytes by task 10857 on cpu 0:

mISDN_read+0x1f2/0x470 drivers/isdn/mISDN/timerdev.c:112

do_loop_readv_writev fs/read_write.c:847 [inline]

vfs_readv+0x3fb/0x690 fs/read_write.c:1020

do_readv+0xe7/0x210 fs/read_write.c:1080

__do_sys_readv fs/read_write.c:1165 [inline]

__se_sys_readv fs/read_write.c:1162 [inline]

__x64_sys_readv+0x45/0x50 fs/read_write.c:1162

x64_sys_call+0x2831/0x3000 arch/x86/include/generated/asm/syscalls_64.h:20

do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]

do_syscall_64+0xd8/0x2c0 arch/x86/entry/syscall_64.c:94

entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000 -> 0x00000001