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159e2db6cb
commit6eb350a223upstream. 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:2a36ab717e("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 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
137 lines
3.1 KiB
C
137 lines
3.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
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#ifndef _LINUX_RSEQ_H
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#define _LINUX_RSEQ_H
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#ifdef CONFIG_RSEQ
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#include <linux/preempt.h>
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#include <linux/sched.h>
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#ifdef CONFIG_MEMBARRIER
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# define RSEQ_EVENT_GUARD irq
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#else
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# define RSEQ_EVENT_GUARD preempt
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#endif
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/*
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* Map the event mask on the user-space ABI enum rseq_cs_flags
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* for direct mask checks.
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*/
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enum rseq_event_mask_bits {
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RSEQ_EVENT_PREEMPT_BIT = RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT_BIT,
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RSEQ_EVENT_SIGNAL_BIT = RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL_BIT,
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RSEQ_EVENT_MIGRATE_BIT = RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE_BIT,
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};
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enum rseq_event_mask {
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RSEQ_EVENT_PREEMPT = (1U << RSEQ_EVENT_PREEMPT_BIT),
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RSEQ_EVENT_SIGNAL = (1U << RSEQ_EVENT_SIGNAL_BIT),
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RSEQ_EVENT_MIGRATE = (1U << RSEQ_EVENT_MIGRATE_BIT),
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};
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static inline void rseq_set_notify_resume(struct task_struct *t)
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{
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if (t->rseq)
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set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
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}
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void __rseq_handle_notify_resume(struct ksignal *sig, struct pt_regs *regs);
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static inline void rseq_handle_notify_resume(struct ksignal *ksig,
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struct pt_regs *regs)
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{
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if (current->rseq)
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__rseq_handle_notify_resume(ksig, regs);
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}
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static inline void rseq_signal_deliver(struct ksignal *ksig,
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struct pt_regs *regs)
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{
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scoped_guard(RSEQ_EVENT_GUARD)
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__set_bit(RSEQ_EVENT_SIGNAL_BIT, ¤t->rseq_event_mask);
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rseq_handle_notify_resume(ksig, regs);
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}
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/* rseq_preempt() requires preemption to be disabled. */
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static inline void rseq_preempt(struct task_struct *t)
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{
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__set_bit(RSEQ_EVENT_PREEMPT_BIT, &t->rseq_event_mask);
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rseq_set_notify_resume(t);
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}
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/* rseq_migrate() requires preemption to be disabled. */
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static inline void rseq_migrate(struct task_struct *t)
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{
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__set_bit(RSEQ_EVENT_MIGRATE_BIT, &t->rseq_event_mask);
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rseq_set_notify_resume(t);
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}
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/*
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* If parent process has a registered restartable sequences area, the
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* child inherits. Unregister rseq for a clone with CLONE_VM set.
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*/
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static inline void rseq_fork(struct task_struct *t, u64 clone_flags)
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{
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if (clone_flags & CLONE_VM) {
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t->rseq = NULL;
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t->rseq_len = 0;
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t->rseq_sig = 0;
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t->rseq_event_mask = 0;
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} else {
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t->rseq = current->rseq;
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t->rseq_len = current->rseq_len;
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t->rseq_sig = current->rseq_sig;
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t->rseq_event_mask = current->rseq_event_mask;
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}
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}
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static inline void rseq_execve(struct task_struct *t)
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{
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t->rseq = NULL;
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t->rseq_len = 0;
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t->rseq_sig = 0;
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t->rseq_event_mask = 0;
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}
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#else
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static inline void rseq_set_notify_resume(struct task_struct *t)
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{
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}
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static inline void rseq_handle_notify_resume(struct ksignal *ksig,
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struct pt_regs *regs)
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{
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}
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static inline void rseq_signal_deliver(struct ksignal *ksig,
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struct pt_regs *regs)
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{
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}
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static inline void rseq_preempt(struct task_struct *t)
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{
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}
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static inline void rseq_migrate(struct task_struct *t)
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{
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}
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static inline void rseq_fork(struct task_struct *t, u64 clone_flags)
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{
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}
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static inline void rseq_execve(struct task_struct *t)
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{
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}
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#endif
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#ifdef CONFIG_DEBUG_RSEQ
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void rseq_syscall(struct pt_regs *regs);
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#else
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static inline void rseq_syscall(struct pt_regs *regs)
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{
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}
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#endif
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#endif /* _LINUX_RSEQ_H */
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