Messages in this thread Patch in this message | | | Date | Fri, 23 Nov 2012 21:28:17 +0100 | From | Oleg Nesterov <> | Subject | [PATCH 7/7] uprobes: _register() should always do register_for_each_vma(true) |
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To support the filtering uprobe_register() should do register_for_each_vma(true) every time the new consumer comes, we need to install the previously nacked breakpoints.
Note: - uprobes_mutex[] should die, what is actually protects is alloc_uprobe().
- UPROBE_RUN_HANDLER should die too, obviously it can't work unless uprobe has a single consumer. The consumer should serialize with _register/_unregister itself. Or this flag should live in uprobe_consumer->state.
- Perhaps we can do some optimizations later. For example, if filter_chain() never returns false uprobe can record this fact and avoid the unnecessary register_for_each_vma().
Signed-off-by: Oleg Nesterov <oleg@redhat.com> --- kernel/events/uprobes.c | 31 +++++++++++++------------------ 1 files changed, 13 insertions(+), 18 deletions(-)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 7c98671..c80507d 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -482,16 +482,12 @@ static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs) up_read(&uprobe->consumer_rwsem); } -/* Returns the previous consumer */ -static struct uprobe_consumer * -consumer_add(struct uprobe *uprobe, struct uprobe_consumer *uc) +static void consumer_add(struct uprobe *uprobe, struct uprobe_consumer *uc) { down_write(&uprobe->consumer_rwsem); uc->next = uprobe->consumers; uprobe->consumers = uc; up_write(&uprobe->consumer_rwsem); - - return uc->next; } /* @@ -820,9 +816,15 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register) return err; } -static int __uprobe_register(struct uprobe *uprobe) +static int __uprobe_register(struct uprobe *uprobe, struct uprobe_consumer *uc) { - return register_for_each_vma(uprobe, true); + int err; + + consumer_add(uprobe, uc); + err = register_for_each_vma(uprobe, true); + if (!err) /* TODO: pointless unless the first consumer */ + set_bit(UPROBE_RUN_HANDLER, &uprobe->flags); + return err; } static void __uprobe_unregister(struct uprobe *uprobe, struct uprobe_consumer *uc) @@ -867,21 +869,14 @@ int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer * if (offset > i_size_read(inode)) return -EINVAL; - ret = 0; + ret = -ENOMEM; mutex_lock(uprobes_hash(inode)); uprobe = alloc_uprobe(inode, offset); - - if (!uprobe) { - ret = -ENOMEM; - } else if (!consumer_add(uprobe, uc)) { - ret = __uprobe_register(uprobe); - if (ret) { + if (uprobe) { + ret = __uprobe_register(uprobe, uc); + if (ret) __uprobe_unregister(uprobe, uc); - } else { - set_bit(UPROBE_RUN_HANDLER, &uprobe->flags); - } } - mutex_unlock(uprobes_hash(inode)); if (uprobe) put_uprobe(uprobe); -- 1.5.5.1
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