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| author | Thomas Gleixner <tglx@linutronix.de> | 2025-08-13 18:02:30 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2025-09-13 20:51:59 +0300 |
| commit | 6eb350a2233100a283f882c023e5ad426d0ed63b (patch) | |
| tree | db0fedfe420652a4ad1fd85fe69dfafb71a930db /include/linux | |
| parent | 76eeb9b8de9880ca38696b2fb56ac45ac0a25c6c (diff) | |
| download | linux-6eb350a2233100a283f882c023e5ad426d0ed63b.tar.xz | |
rseq: Protect event mask against membarrier IPI
rseq_need_restart() reads and clears task::rseq_event_mask with preemption
disabled to guard against the scheduler.
But membarrier() uses an IPI and sets the PREEMPT bit in the event mask
from the IPI, which leaves that RMW operation unprotected.
Use guard(irq) if CONFIG_MEMBARRIER is enabled to fix that.
Fixes: 2a36ab717e8f ("rseq/membarrier: Add MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: stable@vger.kernel.org
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/rseq.h | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/include/linux/rseq.h b/include/linux/rseq.h index bc8af3eb5598..1fbeb61babeb 100644 --- a/include/linux/rseq.h +++ b/include/linux/rseq.h @@ -7,6 +7,12 @@ #include <linux/preempt.h> #include <linux/sched.h> +#ifdef CONFIG_MEMBARRIER +# define RSEQ_EVENT_GUARD irq +#else +# define RSEQ_EVENT_GUARD preempt +#endif + /* * Map the event mask on the user-space ABI enum rseq_cs_flags * for direct mask checks. @@ -41,9 +47,8 @@ static inline void rseq_handle_notify_resume(struct ksignal *ksig, static inline void rseq_signal_deliver(struct ksignal *ksig, struct pt_regs *regs) { - preempt_disable(); - __set_bit(RSEQ_EVENT_SIGNAL_BIT, ¤t->rseq_event_mask); - preempt_enable(); + scoped_guard(RSEQ_EVENT_GUARD) + __set_bit(RSEQ_EVENT_SIGNAL_BIT, ¤t->rseq_event_mask); rseq_handle_notify_resume(ksig, regs); } |