sieni
/
linux
mirror of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
linux/arch/riscv/kernel/vdso
History
Jingwei Wang 5d15d2ad36 riscv: hwprobe: Fix stale vDSO data for late-initialized keys at boot 
The hwprobe vDSO data for some keys, like MISALIGNED_VECTOR_PERF,
is determined by an asynchronous kthread. This can create a race
condition where the kthread finishes after the vDSO data has
already been populated, causing userspace to read stale values.

To fix this race, a new 'ready' flag is added to the vDSO data,
initialized to 'false' during arch_initcall_sync. This flag is
checked by both the vDSO's user-space code and the riscv_hwprobe
syscall. The syscall serves as a one-time gate, using a completion
to wait for any pending probes before populating the data and
setting the flag to 'true', thus ensuring userspace reads fresh
values on its first request.

Reported-by: Tsukasa OI <research_trasio@irq.a4lg.com>
Closes: https://lore.kernel.org/linux-riscv/760d637b-b13b-4518-b6bf-883d55d44e7f@irq.a4lg.com/
Fixes: e7c9d66e31 ("RISC-V: Report vector unaligned access speed hwprobe")
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: stable@vger.kernel.org
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Co-developed-by: Palmer Dabbelt <palmer@dabbelt.com>
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
Signed-off-by: Jingwei Wang <wangjingwei@iscas.ac.cn>
Link: https://lore.kernel.org/r/20250811142035.105820-1-wangjingwei@iscas.ac.cn
[pjw@kernel.org: fix checkpatch issues]
Signed-off-by: Paul Walmsley <pjw@kernel.org>
 		2025-10-17 22:23:11 -06:00
..
.gitignore RISC-V: Fix the VDSO symbol generaton for binutils-2.35+ 2020-11-06 00:03:48 -08:00
Makefile Merge tag 'riscv-mw2-6.16-rc1' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/alexghiti/linux into for-next 2025-06-05 14:03:16 -07:00
flush_icache.S riscv: Use SYM_*() assembly macros instead of deprecated ones 2023-11-06 09:42:47 -08:00
gen_vdso_offsets.sh riscv: explicitly use symbol offsets for VDSO 2021-08-24 21:45:47 -07:00
getcpu.S riscv: Use SYM_*() assembly macros instead of deprecated ones 2023-11-06 09:42:47 -08:00
getrandom.c RISC-V: vDSO: Wire up getrandom() vDSO implementation 2025-06-05 14:03:09 -07:00
hwprobe.c riscv: hwprobe: Fix stale vDSO data for late-initialized keys at boot 2025-10-17 22:23:11 -06:00
note.S riscv: add Linux note to vdso 2020-05-04 14:22:34 -07:00
rt_sigreturn.S riscv: Use SYM_*() assembly macros instead of deprecated ones 2023-11-06 09:42:47 -08:00
sys_hwprobe.S riscv: Use SYM_*() assembly macros instead of deprecated ones 2023-11-06 09:42:47 -08:00
vdso.S riscv: compat: vdso: Add COMPAT_VDSO base code implementation 2022-04-26 13:36:53 -07:00
vdso.lds.S riscv: vdso: Exclude .rodata from the PT_DYNAMIC segment 2025-06-10 13:06:48 -07:00
vgetrandom-chacha.S RISC-V: vDSO: Wire up getrandom() vDSO implementation 2025-06-05 14:03:09 -07:00
vgettimeofday.c arch: vdso: consolidate gettime prototypes 2023-11-23 11:32:32 +01:00