Re: [rfc-patch 07/11] Text Edit Lock - kprobes architecture independent support
* Roel Kluin ([EMAIL PROTECTED]) wrote: [...] > > for (i = 0; i < KPROBE_TABLE_SIZE; i++) { > > head = &kprobe_table[i]; > > + kernel_text_lock(); > > hlist_for_each_entry_rcu(p, node, head, hlist) > > arch_arm_kprobe(p); > > + kernel_text_unlock(); > > } > > isn't it better to put the kernel_text_lock around the for loop? > > > > > kprobe_enabled = true; > > @@ -969,10 +974,12 @@ static void __kprobes disable_all_kprobe > > printk(KERN_INFO "Kprobes globally disabled\n"); > > for (i = 0; i < KPROBE_TABLE_SIZE; i++) { > > head = &kprobe_table[i]; > > + kernel_text_lock(); > > hlist_for_each_entry_rcu(p, node, head, hlist) { > > if (!arch_trampoline_kprobe(p)) > > arch_disarm_kprobe(p); > > } > > + kernel_text_unlock(); > > } > > same question here > Yes, you are right, although it does not have to be fast. Here is the updated patch. Text Edit Lock - kprobes architecture independent support Use the mutual exclusion provided by the text edit lock in the kprobes code. It allows coherent manipulation of the kernel code by other subsystems. Changelog: Move the kernel_text_lock/unlock out of the for loops. Signed-off-by: Mathieu Desnoyers <[EMAIL PROTECTED]> Acked-by: Ananth N Mavinakayanahalli <[EMAIL PROTECTED]> CC: [EMAIL PROTECTED] CC: [EMAIL PROTECTED] CC: [EMAIL PROTECTED] CC: [EMAIL PROTECTED] CC: Roel Kluin <[EMAIL PROTECTED]> --- kernel/kprobes.c | 19 +-- 1 file changed, 13 insertions(+), 6 deletions(-) Index: linux-2.6-lttng/kernel/kprobes.c === --- linux-2.6-lttng.orig/kernel/kprobes.c 2007-11-16 13:40:06.0 -0500 +++ linux-2.6-lttng/kernel/kprobes.c2007-11-17 10:00:23.0 -0500 @@ -43,6 +43,7 @@ #include #include #include +#include #include #include @@ -568,9 +569,10 @@ static int __kprobes __register_kprobe(s goto out; } + kernel_text_lock(); ret = arch_prepare_kprobe(p); if (ret) - goto out; + goto out_unlock_text; INIT_HLIST_NODE(&p->hlist); hlist_add_head_rcu(&p->hlist, @@ -578,7 +580,8 @@ static int __kprobes __register_kprobe(s if (kprobe_enabled) arch_arm_kprobe(p); - +out_unlock_text: + kernel_text_unlock(); out: mutex_unlock(&kprobe_mutex); @@ -621,8 +624,11 @@ valid_p: * enabled - otherwise, the breakpoint would already have * been removed. We save on flushing icache. */ - if (kprobe_enabled) + if (kprobe_enabled) { + kernel_text_lock(); arch_disarm_kprobe(p); + kernel_text_unlock(); + } hlist_del_rcu(&old_p->hlist); cleanup_p = 1; } else { @@ -644,9 +650,7 @@ valid_p: list_del_rcu(&p->list); kfree(old_p); } - mutex_lock(&kprobe_mutex); arch_remove_kprobe(p); - mutex_unlock(&kprobe_mutex); } else { mutex_lock(&kprobe_mutex); if (p->break_handler) @@ -717,7 +721,6 @@ static int __kprobes pre_handler_kretpro ri->rp = rp; ri->task = current; arch_prepare_kretprobe(ri, regs); - /* XXX(hch): why is there no hlist_move_head? */ hlist_del(&ri->uflist); hlist_add_head(&ri->uflist, &ri->rp->used_instances); @@ -938,11 +941,13 @@ static void __kprobes enable_all_kprobes if (kprobe_enabled) goto already_enabled; + kernel_text_lock(); for (i = 0; i < KPROBE_TABLE_SIZE; i++) { head = &kprobe_table[i]; hlist_for_each_entry_rcu(p, node, head, hlist) arch_arm_kprobe(p); } + kernel_text_unlock(); kprobe_enabled = true; printk(KERN_INFO "Kprobes globally enabled\n"); @@ -967,6 +972,7 @@ static void __kprobes disable_all_kprobe kprobe_enabled = false; printk(KERN_INFO "Kprobes globally disabled\n"); + kernel_text_lock(); for (i = 0; i < KPROBE_TABLE_SIZE; i++) { head = &kprobe_table[i]; hlist_for_each_entry_rcu(p, node, head, hlist) { @@ -974,6 +980,7 @@ static void __kprobes disable_all_kprobe arch_disarm_kprobe(p); } } + kernel_text_unlock(); mutex_unlock(&kprobe_mutex); /* Allow all currently running kprobes to complete */ -- Mathieu Desnoyers Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal OpenPGP key fingerprint: 8CD5 52C3 8E
Re: [rfc-patch 07/11] Text Edit Lock - kprobes architecture independent support
Mathieu Desnoyers wrote: > Use the mutual exclusion provided by the text edit lock in the kprobes code. > It > allows coherent manipulation of the kernel code by other subsystems. > > Signed-off-by: Mathieu Desnoyers <[EMAIL PROTECTED]> > Acked-by: Ananth N Mavinakayanahalli <[EMAIL PROTECTED]> > CC: [EMAIL PROTECTED] > CC: [EMAIL PROTECTED] > CC: [EMAIL PROTECTED] > CC: [EMAIL PROTECTED] > --- > kernel/kprobes.c | 19 +-- > 1 file changed, 13 insertions(+), 6 deletions(-) > > Index: linux-2.6-lttng/kernel/kprobes.c > === > --- linux-2.6-lttng.orig/kernel/kprobes.c 2007-09-07 10:12:06.0 > -0400 > +++ linux-2.6-lttng/kernel/kprobes.c 2007-09-07 10:13:09.0 -0400 > @@ -43,6 +43,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -568,9 +569,10 @@ static int __kprobes __register_kprobe(s > goto out; > } > > + kernel_text_lock(); > ret = arch_prepare_kprobe(p); > if (ret) > - goto out; > + goto out_unlock_text; > > INIT_HLIST_NODE(&p->hlist); > hlist_add_head_rcu(&p->hlist, > @@ -578,7 +580,8 @@ static int __kprobes __register_kprobe(s > > if (kprobe_enabled) > arch_arm_kprobe(p); > - > +out_unlock_text: > + kernel_text_unlock(); > out: > mutex_unlock(&kprobe_mutex); > > @@ -621,8 +624,11 @@ valid_p: >* enabled - otherwise, the breakpoint would already have >* been removed. We save on flushing icache. >*/ > - if (kprobe_enabled) > + if (kprobe_enabled) { > + kernel_text_lock(); > arch_disarm_kprobe(p); > + kernel_text_unlock(); > + } > hlist_del_rcu(&old_p->hlist); > cleanup_p = 1; > } else { > @@ -644,9 +650,7 @@ valid_p: > list_del_rcu(&p->list); > kfree(old_p); > } > - mutex_lock(&kprobe_mutex); > arch_remove_kprobe(p); > - mutex_unlock(&kprobe_mutex); > } else { > mutex_lock(&kprobe_mutex); > if (p->break_handler) > @@ -717,7 +721,6 @@ static int __kprobes pre_handler_kretpro > ri->rp = rp; > ri->task = current; > arch_prepare_kretprobe(ri, regs); > - > /* XXX(hch): why is there no hlist_move_head? */ > hlist_del(&ri->uflist); > hlist_add_head(&ri->uflist, &ri->rp->used_instances); > @@ -940,8 +943,10 @@ static void __kprobes enable_all_kprobes > > for (i = 0; i < KPROBE_TABLE_SIZE; i++) { > head = &kprobe_table[i]; > + kernel_text_lock(); > hlist_for_each_entry_rcu(p, node, head, hlist) > arch_arm_kprobe(p); > + kernel_text_unlock(); > } isn't it better to put the kernel_text_lock around the for loop? > > kprobe_enabled = true; > @@ -969,10 +974,12 @@ static void __kprobes disable_all_kprobe > printk(KERN_INFO "Kprobes globally disabled\n"); > for (i = 0; i < KPROBE_TABLE_SIZE; i++) { > head = &kprobe_table[i]; > + kernel_text_lock(); > hlist_for_each_entry_rcu(p, node, head, hlist) { > if (!arch_trampoline_kprobe(p)) > arch_disarm_kprobe(p); > } > + kernel_text_unlock(); > } same question here > > mutex_unlock(&kprobe_mutex); > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[rfc-patch 07/11] Text Edit Lock - kprobes architecture independent support
Use the mutual exclusion provided by the text edit lock in the kprobes code. It allows coherent manipulation of the kernel code by other subsystems. Signed-off-by: Mathieu Desnoyers <[EMAIL PROTECTED]> Acked-by: Ananth N Mavinakayanahalli <[EMAIL PROTECTED]> CC: [EMAIL PROTECTED] CC: [EMAIL PROTECTED] CC: [EMAIL PROTECTED] CC: [EMAIL PROTECTED] --- kernel/kprobes.c | 19 +-- 1 file changed, 13 insertions(+), 6 deletions(-) Index: linux-2.6-lttng/kernel/kprobes.c === --- linux-2.6-lttng.orig/kernel/kprobes.c 2007-09-07 10:12:06.0 -0400 +++ linux-2.6-lttng/kernel/kprobes.c2007-09-07 10:13:09.0 -0400 @@ -43,6 +43,7 @@ #include #include #include +#include #include #include @@ -568,9 +569,10 @@ static int __kprobes __register_kprobe(s goto out; } + kernel_text_lock(); ret = arch_prepare_kprobe(p); if (ret) - goto out; + goto out_unlock_text; INIT_HLIST_NODE(&p->hlist); hlist_add_head_rcu(&p->hlist, @@ -578,7 +580,8 @@ static int __kprobes __register_kprobe(s if (kprobe_enabled) arch_arm_kprobe(p); - +out_unlock_text: + kernel_text_unlock(); out: mutex_unlock(&kprobe_mutex); @@ -621,8 +624,11 @@ valid_p: * enabled - otherwise, the breakpoint would already have * been removed. We save on flushing icache. */ - if (kprobe_enabled) + if (kprobe_enabled) { + kernel_text_lock(); arch_disarm_kprobe(p); + kernel_text_unlock(); + } hlist_del_rcu(&old_p->hlist); cleanup_p = 1; } else { @@ -644,9 +650,7 @@ valid_p: list_del_rcu(&p->list); kfree(old_p); } - mutex_lock(&kprobe_mutex); arch_remove_kprobe(p); - mutex_unlock(&kprobe_mutex); } else { mutex_lock(&kprobe_mutex); if (p->break_handler) @@ -717,7 +721,6 @@ static int __kprobes pre_handler_kretpro ri->rp = rp; ri->task = current; arch_prepare_kretprobe(ri, regs); - /* XXX(hch): why is there no hlist_move_head? */ hlist_del(&ri->uflist); hlist_add_head(&ri->uflist, &ri->rp->used_instances); @@ -940,8 +943,10 @@ static void __kprobes enable_all_kprobes for (i = 0; i < KPROBE_TABLE_SIZE; i++) { head = &kprobe_table[i]; + kernel_text_lock(); hlist_for_each_entry_rcu(p, node, head, hlist) arch_arm_kprobe(p); + kernel_text_unlock(); } kprobe_enabled = true; @@ -969,10 +974,12 @@ static void __kprobes disable_all_kprobe printk(KERN_INFO "Kprobes globally disabled\n"); for (i = 0; i < KPROBE_TABLE_SIZE; i++) { head = &kprobe_table[i]; + kernel_text_lock(); hlist_for_each_entry_rcu(p, node, head, hlist) { if (!arch_trampoline_kprobe(p)) arch_disarm_kprobe(p); } + kernel_text_unlock(); } mutex_unlock(&kprobe_mutex); -- Mathieu Desnoyers Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/