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 mISDNread() and mISDNpoll(). Add READONCE()/WRITEONCE() annotations.

BUG: KCSAN: data-race in mISDNioctl / mISDNread

write to 0xffff88812d848280 of 4 bytes by task 10864 on cpu 1: misdnaddtimer drivers/isdn/mISDN/timerdev.c:175 [inline] mISDNioctl+0x2fb/0x550 drivers/isdn/mISDN/timerdev.c:233 vfsioctl fs/ioctl.c:51 [inline] __dosysioctl fs/ioctl.c:597 [inline] __sesysioctl+0xce/0x140 fs/ioctl.c:583 _x64sysioctl+0x43/0x50 fs/ioctl.c:583 x64syscall+0x14b0/0x3000 arch/x86/include/generated/asm/syscalls64.h:17 dosyscallx64 arch/x86/entry/syscall64.c:63 [inline] dosyscall64+0xd8/0x2c0 arch/x86/entry/syscall64.c:94 entrySYSCALL64afterhwframe+0x77/0x7f

read to 0xffff88812d848280 of 4 bytes by task 10857 on cpu 0: mISDNread+0x1f2/0x470 drivers/isdn/mISDN/timerdev.c:112 doloopreadvwritev fs/readwrite.c:847 [inline] vfsreadv+0x3fb/0x690 fs/readwrite.c:1020 doreadv+0xe7/0x210 fs/read_write.c:1080 __dosysreadv fs/read_write.c:1165 [inline] __sesysreadv fs/read_write.c:1162 [inline] __x64sysreadv+0x45/0x50 fs/readwrite.c:1162 x64syscall+0x2831/0x3000 arch/x86/include/generated/asm/syscalls64.h:20 dosyscallx64 arch/x86/entry/syscall64.c:63 [inline] dosyscall64+0xd8/0x2c0 arch/x86/entry/syscall64.c:94 entrySYSCALL64afterhwframe+0x77/0x7f

value changed: 0x00000000 -> 0x00000001