With uprobe_unregister() having grown a synchronize_srcu(), it becomes fairly slow to call. Esp. since both users of this API call it in a loop.
Peel off the sync_srcu() and do it once, after the loop. Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Acked-by: Masami Hiramatsu (Google) <mhira...@kernel.org> --- include/linux/uprobes.h | 8 ++++++-- kernel/events/uprobes.c | 8 ++++++-- kernel/trace/bpf_trace.c | 6 ++++-- kernel/trace/trace_uprobe.c | 6 +++++- 4 files changed, 21 insertions(+), 7 deletions(-) --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -113,7 +113,8 @@ extern int uprobe_write_opcode(struct ar extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc); extern int uprobe_register_refctr(struct inode *inode, loff_t offset, loff_t ref_ctr_offset, struct uprobe_consumer *uc); extern int uprobe_apply(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, bool); -extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc); +extern void uprobe_unregister_nosync(struct inode *inode, loff_t offset, struct uprobe_consumer *uc); +extern void uprobe_unregister_sync(void); extern int uprobe_mmap(struct vm_area_struct *vma); extern void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end); extern void uprobe_start_dup_mmap(void); @@ -163,7 +164,10 @@ uprobe_apply(struct inode *inode, loff_t return -ENOSYS; } static inline void -uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) +uprobe_unregister_nosync(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) +{ +} +static inline void uprobes_unregister_sync(void) { } static inline int uprobe_mmap(struct vm_area_struct *vma) --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1138,7 +1138,7 @@ __uprobe_unregister(struct uprobe *uprob * @offset: offset from the start of the file. * @uc: identify which probe if multiple probes are colocated. */ -void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) +void uprobe_unregister_nosync(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) { struct uprobe *uprobe; @@ -1152,10 +1152,14 @@ void uprobe_unregister(struct inode *ino raw_write_seqcount_end(&uprobe->register_seq); up_write(&uprobe->register_rwsem); put_uprobe(uprobe); +} +EXPORT_SYMBOL_GPL(uprobe_unregister_nosync); +void uprobe_unregister_sync(void) +{ synchronize_srcu(&uprobes_srcu); } -EXPORT_SYMBOL_GPL(uprobe_unregister); +EXPORT_SYMBOL_GPL(uprobe_unregister_sync); /* * __uprobe_register - register a probe --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -3181,9 +3181,11 @@ static void bpf_uprobe_unregister(struct u32 i; for (i = 0; i < cnt; i++) { - uprobe_unregister(d_real_inode(path->dentry), uprobes[i].offset, - &uprobes[i].consumer); + uprobe_unregister_nosync(d_real_inode(path->dentry), uprobes[i].offset, + &uprobes[i].consumer); } + if (cnt) + uprobe_unregister_sync(); } static void bpf_uprobe_multi_link_release(struct bpf_link *link) --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -1104,6 +1104,7 @@ static int trace_uprobe_enable(struct tr static void __probe_event_disable(struct trace_probe *tp) { struct trace_uprobe *tu; + bool sync = false; tu = container_of(tp, struct trace_uprobe, tp); WARN_ON(!uprobe_filter_is_empty(tu->tp.event->filter)); @@ -1112,9 +1113,12 @@ static void __probe_event_disable(struct if (!tu->inode) continue; - uprobe_unregister(tu->inode, tu->offset, &tu->consumer); + uprobe_unregister_nosync(tu->inode, tu->offset, &tu->consumer); + sync = true; tu->inode = NULL; } + if (sync) + uprobe_unregister_sync(); } static int probe_event_enable(struct trace_event_call *call,