From: "Paul E. McKenney" <paulmck@us.ibm.com>
To: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: linux-kernel@vger.kernel.org, akpm@osdl.org,
anil.s.keshavamurthy@intel.com, davem@davemloft.net,
prasanna@in.ibm.com
Subject: Re: [PATCH 9/9] Kprobes: Use RCU for (un)register synchronization - arch changes
Date: Tue, 18 Oct 2005 09:35:09 -0700 [thread overview]
Message-ID: <20051018163509.GC1304@us.ibm.com> (raw)
In-Reply-To: <20051018144526.GA4623@in.ibm.com>
On Tue, Oct 18, 2005 at 10:45:26AM -0400, Ananth N Mavinakayanahalli wrote:
> On Mon, Oct 17, 2005 at 10:49:30PM -0700, Paul E. McKenney wrote:
> > On Mon, Oct 10, 2005 at 10:48:13AM -0400, Ananth N Mavinakayanahalli wrote:
> > > From: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
> > >
> > > Changes to the arch kprobes infrastructure to take advantage of the locking
> > > changes introduced by usage of RCU for synchronization. All handlers are
> > > now run without any locks held, so they have to be re-entrant or provide
> > > their own synchronization.
> >
> > And a few very similar questions here as well...
>
> Replies inline...
>
> Ananth
Rereplies also inline!
> > Thanx, Paul
> >
> > > Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
> > > Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
> > > ---
> > >
> > > arch/i386/kernel/kprobes.c | 22 +++++++---------------
> > > arch/ia64/kernel/kprobes.c | 16 ++++++----------
> > > arch/ppc64/kernel/kprobes.c | 24 ++++++------------------
> > > arch/sparc64/kernel/kprobes.c | 14 ++------------
> > > arch/x86_64/kernel/kprobes.c | 25 ++++++-------------------
> > > 5 files changed, 27 insertions(+), 74 deletions(-)
> > >
> > > Index: linux-2.6.14-rc3/arch/i386/kernel/kprobes.c
> > > ===================================================================
> > > --- linux-2.6.14-rc3.orig/arch/i386/kernel/kprobes.c 2005-10-05 16:08:13.000000000 -0400
> > > +++ linux-2.6.14-rc3/arch/i386/kernel/kprobes.c 2005-10-05 16:08:48.000000000 -0400
> > > @@ -31,7 +31,6 @@
> > > #include <linux/config.h>
> > > #include <linux/kprobes.h>
> > > #include <linux/ptrace.h>
> > > -#include <linux/spinlock.h>
> > > #include <linux/preempt.h>
> > > #include <asm/cacheflush.h>
> > > #include <asm/kdebug.h>
> > > @@ -123,6 +122,7 @@ static inline void prepare_singlestep(st
> > > regs->eip = (unsigned long)&p->ainsn.insn;
> > > }
> > >
> > > +/* Called with kretprobe_lock held */
> > > void __kprobes arch_prepare_kretprobe(struct kretprobe *rp,
> > > struct pt_regs *regs)
> > > {
> > > @@ -168,15 +168,12 @@ static int __kprobes kprobe_handler(stru
> > > }
> > > /* Check we're not actually recursing */
> > > if (kprobe_running()) {
> > > - /* We *are* holding lock here, so this is safe.
> > > - Disarm the probe we just hit, and ignore it. */
> > > p = get_kprobe(addr);
> > > if (p) {
> > > if (kcb->kprobe_status == KPROBE_HIT_SS &&
> > > *p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
> > > regs->eflags &= ~TF_MASK;
> > > regs->eflags |= kcb->kprobe_saved_eflags;
> > > - unlock_kprobes();
> > > goto no_kprobe;
> > > }
> > > /* We have reentered the kprobe_handler(), since
> > > @@ -197,14 +194,11 @@ static int __kprobes kprobe_handler(stru
> > > goto ss_probe;
> > > }
> > > }
> > > - /* If it's not ours, can't be delete race, (we hold lock). */
> > > goto no_kprobe;
> > > }
> > >
> > > - lock_kprobes();
> > > p = get_kprobe(addr);
> > > if (!p) {
> > > - unlock_kprobes();
> > > if (regs->eflags & VM_MASK) {
> > > /* We are in virtual-8086 mode. Return 0 */
> > > goto no_kprobe;
> > > @@ -268,9 +262,10 @@ int __kprobes trampoline_probe_handler(s
> > > struct kretprobe_instance *ri = NULL;
> > > struct hlist_head *head;
> > > struct hlist_node *node, *tmp;
> > > - unsigned long orig_ret_address = 0;
> > > + unsigned long flags, orig_ret_address = 0;
> > > unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
> > >
> > > + spin_lock_irqsave(&kretprobe_lock, flags);
> > > head = kretprobe_inst_table_head(current);
> > >
> > > /*
> > > @@ -310,7 +305,7 @@ int __kprobes trampoline_probe_handler(s
> > > regs->eip = orig_ret_address;
> > >
> > > reset_current_kprobe();
> > > - unlock_kprobes();
> > > + spin_unlock_irqrestore(&kretprobe_lock, flags);
> > > preempt_enable_no_resched();
> > >
> > > /*
> > > @@ -395,7 +390,7 @@ static void __kprobes resume_execution(s
> > >
> > > /*
> > > * Interrupts are disabled on entry as trap1 is an interrupt gate and they
> > > - * remain disabled thoroughout this function. And we hold kprobe lock.
> > > + * remain disabled thoroughout this function.
> > > */
> > > static inline int post_kprobe_handler(struct pt_regs *regs)
> > > {
> > > @@ -419,7 +414,6 @@ static inline int post_kprobe_handler(st
> > > goto out;
> > > }
> > > reset_current_kprobe();
> > > - unlock_kprobes();
> > > out:
> > > preempt_enable_no_resched();
> > >
> > > @@ -434,7 +428,6 @@ out:
> > > return 1;
> > > }
> > >
> > > -/* Interrupts disabled, kprobe_lock held. */
> > > static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
> > > {
> > > struct kprobe *cur = kprobe_running();
> > > @@ -448,7 +441,6 @@ static inline int kprobe_fault_handler(s
> > > regs->eflags |= kcb->kprobe_old_eflags;
> > >
> > > reset_current_kprobe();
> > > - unlock_kprobes();
> > > preempt_enable_no_resched();
> > > }
> > > return 0;
> > > @@ -463,7 +455,7 @@ int __kprobes kprobe_exceptions_notify(s
> > > struct die_args *args = (struct die_args *)data;
> > > int ret = NOTIFY_DONE;
> > >
> > > - preempt_disable();
> > > + rcu_read_lock();
> >
> > If synchronize_sched() is used on the update side, this needs to
> > remain preempt_disable() rather than rcu_read_lock().
>
> Kprobe handlers can't block/sleep. So the idea is to depend on a
> schedule() event to ensure handlers have executed. This and the others
> you have pointed out can surely be preempt_disable().
Yep! Or maybe you can rely on the preempt_disable() that guards the
single-step operation?
> > > switch (val) {
> > > case DIE_INT3:
> > > if (kprobe_handler(args->regs))
> > > @@ -482,7 +474,7 @@ int __kprobes kprobe_exceptions_notify(s
> > > default:
> > > break;
> > > }
> > > - preempt_enable();
> > > + rcu_read_unlock();
> > > return ret;
> > > }
> > >
> > > Index: linux-2.6.14-rc3/arch/ia64/kernel/kprobes.c
> > > ===================================================================
> > > --- linux-2.6.14-rc3.orig/arch/ia64/kernel/kprobes.c 2005-10-05 16:08:14.000000000 -0400
> > > +++ linux-2.6.14-rc3/arch/ia64/kernel/kprobes.c 2005-10-05 16:08:48.000000000 -0400
> > > @@ -26,7 +26,6 @@
> > > #include <linux/config.h>
> > > #include <linux/kprobes.h>
> > > #include <linux/ptrace.h>
> > > -#include <linux/spinlock.h>
> > > #include <linux/string.h>
> > > #include <linux/slab.h>
> > > #include <linux/preempt.h>
> > > @@ -343,10 +342,11 @@ int __kprobes trampoline_probe_handler(s
> > > struct kretprobe_instance *ri = NULL;
> > > struct hlist_head *head;
> > > struct hlist_node *node, *tmp;
> > > - unsigned long orig_ret_address = 0;
> > > + unsigned long flags, orig_ret_address = 0;
> > > unsigned long trampoline_address =
> > > ((struct fnptr *)kretprobe_trampoline)->ip;
> > >
> > > + spin_lock_irqsave(&kretprobe_lock, flags);
> > > head = kretprobe_inst_table_head(current);
> > >
> > > /*
> > > @@ -386,7 +386,7 @@ int __kprobes trampoline_probe_handler(s
> > > regs->cr_iip = orig_ret_address;
> > >
> > > reset_current_kprobe();
> > > - unlock_kprobes();
> > > + spin_unlock_irqrestore(&kretprobe_lock, flags);
> > > preempt_enable_no_resched();
> > >
> > > /*
> > > @@ -397,6 +397,7 @@ int __kprobes trampoline_probe_handler(s
> > > return 1;
> > > }
> > >
> > > +/* Called with kretprobe_lock held */
> > > void __kprobes arch_prepare_kretprobe(struct kretprobe *rp,
> > > struct pt_regs *regs)
> > > {
> > > @@ -612,7 +613,6 @@ static int __kprobes pre_kprobes_handler
> > > if ((kcb->kprobe_status == KPROBE_HIT_SS) &&
> > > (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)) {
> > > ia64_psr(regs)->ss = 0;
> > > - unlock_kprobes();
> > > goto no_kprobe;
> > > }
> > > /* We have reentered the pre_kprobe_handler(), since
> > > @@ -641,10 +641,8 @@ static int __kprobes pre_kprobes_handler
> > > }
> > > }
> > >
> > > - lock_kprobes();
> > > p = get_kprobe(addr);
> > > if (!p) {
> > > - unlock_kprobes();
> > > if (!is_ia64_break_inst(regs)) {
> > > /*
> > > * The breakpoint instruction was removed right
> > > @@ -707,7 +705,6 @@ static int __kprobes post_kprobes_handle
> > > goto out;
> > > }
> > > reset_current_kprobe();
> > > - unlock_kprobes();
> > >
> > > out:
> > > preempt_enable_no_resched();
> > > @@ -728,7 +725,6 @@ static int __kprobes kprobes_fault_handl
> > > if (kcb->kprobe_status & KPROBE_HIT_SS) {
> > > resume_execution(cur, regs);
> > > reset_current_kprobe();
> > > - unlock_kprobes();
> > > preempt_enable_no_resched();
> > > }
> > >
> > > @@ -741,7 +737,7 @@ int __kprobes kprobe_exceptions_notify(s
> > > struct die_args *args = (struct die_args *)data;
> > > int ret = NOTIFY_DONE;
> > >
> > > - preempt_disable();
> > > + rcu_read_lock();
> >
> > Ditto here...
> >
> > > switch(val) {
> > > case DIE_BREAK:
> > > if (pre_kprobes_handler(args))
> > > @@ -757,7 +753,7 @@ int __kprobes kprobe_exceptions_notify(s
> > > default:
> > > break;
> > > }
> > > - preempt_enable();
> > > + rcu_read_unlock();
> > > return ret;
> > > }
> > >
> > > Index: linux-2.6.14-rc3/arch/ppc64/kernel/kprobes.c
> > > ===================================================================
> > > --- linux-2.6.14-rc3.orig/arch/ppc64/kernel/kprobes.c 2005-10-05 16:08:15.000000000 -0400
> > > +++ linux-2.6.14-rc3/arch/ppc64/kernel/kprobes.c 2005-10-05 16:08:48.000000000 -0400
> > > @@ -30,7 +30,6 @@
> > > #include <linux/config.h>
> > > #include <linux/kprobes.h>
> > > #include <linux/ptrace.h>
> > > -#include <linux/spinlock.h>
> > > #include <linux/preempt.h>
> > > #include <asm/cacheflush.h>
> > > #include <asm/kdebug.h>
> > > @@ -125,6 +124,7 @@ static inline void set_current_kprobe(st
> > > kcb->kprobe_saved_msr = regs->msr;
> > > }
> > >
> > > +/* Called with kretprobe_lock held */
> > > void __kprobes arch_prepare_kretprobe(struct kretprobe *rp,
> > > struct pt_regs *regs)
> > > {
> > > @@ -152,8 +152,6 @@ static inline int kprobe_handler(struct
> > >
> > > /* Check we're not actually recursing */
> > > if (kprobe_running()) {
> > > - /* We *are* holding lock here, so this is safe.
> > > - Disarm the probe we just hit, and ignore it. */
> > > p = get_kprobe(addr);
> > > if (p) {
> > > kprobe_opcode_t insn = *p->ainsn.insn;
> > > @@ -161,7 +159,6 @@ static inline int kprobe_handler(struct
> > > is_trap(insn)) {
> > > regs->msr &= ~MSR_SE;
> > > regs->msr |= kcb->kprobe_saved_msr;
> > > - unlock_kprobes();
> > > goto no_kprobe;
> > > }
> > > /* We have reentered the kprobe_handler(), since
> > > @@ -183,14 +180,11 @@ static inline int kprobe_handler(struct
> > > goto ss_probe;
> > > }
> > > }
> > > - /* If it's not ours, can't be delete race, (we hold lock). */
> > > goto no_kprobe;
> > > }
> > >
> > > - lock_kprobes();
> > > p = get_kprobe(addr);
> > > if (!p) {
> > > - unlock_kprobes();
> > > if (*addr != BREAKPOINT_INSTRUCTION) {
> > > /*
> > > * PowerPC has multiple variants of the "trap"
> > > @@ -254,9 +248,10 @@ int __kprobes trampoline_probe_handler(s
> > > struct kretprobe_instance *ri = NULL;
> > > struct hlist_head *head;
> > > struct hlist_node *node, *tmp;
> > > - unsigned long orig_ret_address = 0;
> > > + unsigned long flags, orig_ret_address = 0;
> > > unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
> > >
> > > + spin_lock_irqsave(&kretprobe_lock, flags);
> > > head = kretprobe_inst_table_head(current);
> > >
> > > /*
> > > @@ -296,7 +291,7 @@ int __kprobes trampoline_probe_handler(s
> > > regs->nip = orig_ret_address;
> > >
> > > reset_current_kprobe();
> > > - unlock_kprobes();
> > > + spin_unlock_irqrestore(&kretprobe_lock, flags);
> > > preempt_enable_no_resched();
> > >
> > > /*
> > > @@ -348,7 +343,6 @@ static inline int post_kprobe_handler(st
> > > goto out;
> > > }
> > > reset_current_kprobe();
> > > - unlock_kprobes();
> > > out:
> > > preempt_enable_no_resched();
> > >
> > > @@ -363,7 +357,6 @@ out:
> > > return 1;
> > > }
> > >
> > > -/* Interrupts disabled, kprobe_lock held. */
> > > static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
> > > {
> > > struct kprobe *cur = kprobe_running();
> > > @@ -378,7 +371,6 @@ static inline int kprobe_fault_handler(s
> > > regs->msr |= kcb->kprobe_saved_msr;
> > >
> > > reset_current_kprobe();
> > > - unlock_kprobes();
> > > preempt_enable_no_resched();
> > > }
> > > return 0;
> > > @@ -393,11 +385,7 @@ int __kprobes kprobe_exceptions_notify(s
> > > struct die_args *args = (struct die_args *)data;
> > > int ret = NOTIFY_DONE;
> > >
> > > - /*
> > > - * Interrupts are not disabled here. We need to disable
> > > - * preemption, because kprobe_running() uses smp_processor_id().
> > > - */
> > > - preempt_disable();
> > > + rcu_read_lock();
> >
> > And here...
> >
> > > switch (val) {
> > > case DIE_BPT:
> > > if (kprobe_handler(args->regs))
> > > @@ -416,7 +404,7 @@ int __kprobes kprobe_exceptions_notify(s
> > > default:
> > > break;
> > > }
> > > - preempt_enable_no_resched();
> > > + rcu_read_unlock();
> > > return ret;
> > > }
> > >
> > > Index: linux-2.6.14-rc3/arch/sparc64/kernel/kprobes.c
> > > ===================================================================
> > > --- linux-2.6.14-rc3.orig/arch/sparc64/kernel/kprobes.c 2005-10-05 16:08:15.000000000 -0400
> > > +++ linux-2.6.14-rc3/arch/sparc64/kernel/kprobes.c 2005-10-05 16:08:48.000000000 -0400
> > > @@ -116,15 +116,11 @@ static int __kprobes kprobe_handler(stru
> > > struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
> > >
> > > if (kprobe_running()) {
> > > - /* We *are* holding lock here, so this is safe.
> > > - * Disarm the probe we just hit, and ignore it.
> > > - */
> > > p = get_kprobe(addr);
> > > if (p) {
> > > if (kcb->kprobe_status == KPROBE_HIT_SS) {
> > > regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
> > > kcb->kprobe_orig_tstate_pil);
> > > - unlock_kprobes();
> > > goto no_kprobe;
> > > }
> > > /* We have reentered the kprobe_handler(), since
> > > @@ -144,14 +140,11 @@ static int __kprobes kprobe_handler(stru
> > > if (p->break_handler && p->break_handler(p, regs))
> > > goto ss_probe;
> > > }
> > > - /* If it's not ours, can't be delete race, (we hold lock). */
> > > goto no_kprobe;
> > > }
> > >
> > > - lock_kprobes();
> > > p = get_kprobe(addr);
> > > if (!p) {
> > > - unlock_kprobes();
> > > if (*(u32 *)addr != BREAKPOINT_INSTRUCTION) {
> > > /*
> > > * The breakpoint instruction was removed right
> > > @@ -296,14 +289,12 @@ static inline int post_kprobe_handler(st
> > > goto out;
> > > }
> > > reset_current_kprobe();
> > > - unlock_kprobes();
> > > out:
> > > preempt_enable_no_resched();
> > >
> > > return 1;
> > > }
> > >
> > > -/* Interrupts disabled, kprobe_lock held. */
> > > static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
> > > {
> > > struct kprobe *cur = kprobe_running();
> > > @@ -316,7 +307,6 @@ static inline int kprobe_fault_handler(s
> > > resume_execution(cur, regs, kcb);
> > >
> > > reset_current_kprobe();
> > > - unlock_kprobes();
> > > preempt_enable_no_resched();
> > > }
> > > return 0;
> > > @@ -331,7 +321,7 @@ int __kprobes kprobe_exceptions_notify(s
> > > struct die_args *args = (struct die_args *)data;
> > > int ret = NOTIFY_DONE;
> > >
> > > - preempt_disable();
> > > + rcu_read_lock();
> >
> > As well as here...
> >
> > > switch (val) {
> > > case DIE_DEBUG:
> > > if (kprobe_handler(args->regs))
> > > @@ -350,7 +340,7 @@ int __kprobes kprobe_exceptions_notify(s
> > > default:
> > > break;
> > > }
> > > - preempt_enable();
> > > + rcu_read_unlock();
> > > return ret;
> > > }
> > >
> > > Index: linux-2.6.14-rc3/arch/x86_64/kernel/kprobes.c
> > > ===================================================================
> > > --- linux-2.6.14-rc3.orig/arch/x86_64/kernel/kprobes.c 2005-10-05 16:08:33.000000000 -0400
> > > +++ linux-2.6.14-rc3/arch/x86_64/kernel/kprobes.c 2005-10-05 16:08:48.000000000 -0400
> > > @@ -34,7 +34,6 @@
> > > #include <linux/config.h>
> > > #include <linux/kprobes.h>
> > > #include <linux/ptrace.h>
> > > -#include <linux/spinlock.h>
> > > #include <linux/string.h>
> > > #include <linux/slab.h>
> > > #include <linux/preempt.h>
> > > @@ -266,6 +265,7 @@ static void __kprobes prepare_singlestep
> > > regs->rip = (unsigned long)p->ainsn.insn;
> > > }
> > >
> > > +/* Called with kretprobe_lock held */
> > > void __kprobes arch_prepare_kretprobe(struct kretprobe *rp,
> > > struct pt_regs *regs)
> > > {
> > > @@ -299,15 +299,12 @@ int __kprobes kprobe_handler(struct pt_r
> > >
> > > /* Check we're not actually recursing */
> > > if (kprobe_running()) {
> > > - /* We *are* holding lock here, so this is safe.
> > > - Disarm the probe we just hit, and ignore it. */
> > > p = get_kprobe(addr);
> > > if (p) {
> > > if (kcb->kprobe_status == KPROBE_HIT_SS &&
> > > *p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
> > > regs->eflags &= ~TF_MASK;
> > > regs->eflags |= kcb->kprobe_saved_rflags;
> > > - unlock_kprobes();
> > > goto no_kprobe;
> > > } else if (kcb->kprobe_status == KPROBE_HIT_SSDONE) {
> > > /* TODO: Provide re-entrancy from
> > > @@ -340,14 +337,11 @@ int __kprobes kprobe_handler(struct pt_r
> > > goto ss_probe;
> > > }
> > > }
> > > - /* If it's not ours, can't be delete race, (we hold lock). */
> > > goto no_kprobe;
> > > }
> > >
> > > - lock_kprobes();
> > > p = get_kprobe(addr);
> > > if (!p) {
> > > - unlock_kprobes();
> > > if (*addr != BREAKPOINT_INSTRUCTION) {
> > > /*
> > > * The breakpoint instruction was removed right
> > > @@ -406,9 +400,10 @@ int __kprobes trampoline_probe_handler(s
> > > struct kretprobe_instance *ri = NULL;
> > > struct hlist_head *head;
> > > struct hlist_node *node, *tmp;
> > > - unsigned long orig_ret_address = 0;
> > > + unsigned long flags, orig_ret_address = 0;
> > > unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
> > >
> > > + spin_lock_irqsave(&kretprobe_lock, flags);
> > > head = kretprobe_inst_table_head(current);
> > >
> > > /*
> > > @@ -448,7 +443,7 @@ int __kprobes trampoline_probe_handler(s
> > > regs->rip = orig_ret_address;
> > >
> > > reset_current_kprobe();
> > > - unlock_kprobes();
> > > + spin_unlock_irqrestore(&kretprobe_lock, flags);
> > > preempt_enable_no_resched();
> > >
> > > /*
> > > @@ -536,10 +531,6 @@ static void __kprobes resume_execution(s
> > > }
> > > }
> > >
> > > -/*
> > > - * Interrupts are disabled on entry as trap1 is an interrupt gate and they
> > > - * remain disabled thoroughout this function. And we hold kprobe lock.
> > > - */
> > > int __kprobes post_kprobe_handler(struct pt_regs *regs)
> > > {
> > > struct kprobe *cur = kprobe_running();
> > > @@ -560,8 +551,6 @@ int __kprobes post_kprobe_handler(struct
> > > if (kcb->kprobe_status == KPROBE_REENTER) {
> > > restore_previous_kprobe(kcb);
> > > goto out;
> > > - } else {
> > > - unlock_kprobes();
> > > }
> > > reset_current_kprobe();
> > > out:
> > > @@ -578,7 +567,6 @@ out:
> > > return 1;
> > > }
> > >
> > > -/* Interrupts disabled, kprobe_lock held. */
> > > int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
> > > {
> > > struct kprobe *cur = kprobe_running();
> > > @@ -592,7 +580,6 @@ int __kprobes kprobe_fault_handler(struc
> > > regs->eflags |= kcb->kprobe_old_rflags;
> > >
> > > reset_current_kprobe();
> > > - unlock_kprobes();
> > > preempt_enable_no_resched();
> > > }
> > > return 0;
> > > @@ -607,7 +594,7 @@ int __kprobes kprobe_exceptions_notify(s
> > > struct die_args *args = (struct die_args *)data;
> > > int ret = NOTIFY_DONE;
> > >
> > > - preempt_disable();
> > > + rcu_read_lock();
> >
> > As well as here yet again...
> >
> > > switch (val) {
> > > case DIE_INT3:
> > > if (kprobe_handler(args->regs))
> > > @@ -626,7 +613,7 @@ int __kprobes kprobe_exceptions_notify(s
> > > default:
> > > break;
> > > }
> > > - preempt_enable();
> > > + rcu_read_unlock();
> > > return ret;
> > > }
> > >
> > > -
> > > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> > > the body of a message to majordomo@vger.kernel.org
> > > More majordomo info at http://vger.kernel.org/majordomo-info.html
> > > Please read the FAQ at http://www.tux.org/lkml/
> > >
> > >
>
next prev parent reply other threads:[~2005-10-18 16:34 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-10-10 14:37 [PATCH 0/9] Kprobes: scalability enhancements Ananth N Mavinakayanahalli
2005-10-10 14:39 ` [PATCH 1/9] Kprobes: rearrange preempt_disable/enable() calls Ananth N Mavinakayanahalli
2005-10-10 14:41 ` [PATCH 2/9] Kprobes: Track kprobe on a per_cpu basis - base changes Ananth N Mavinakayanahalli
2005-10-10 14:42 ` [PATCH 3/9] Kprobes: Track kprobe on a per_cpu basis - i386 changes Ananth N Mavinakayanahalli
2005-10-10 14:42 ` [PATCH 4/9] Kprobes: Track kprobe on a per_cpu basis - ia64 changes Ananth N Mavinakayanahalli
2005-10-10 14:43 ` [PATCH 5/9] Kprobes: Track kprobe on a per_cpu basis - ppc64 changes Ananth N Mavinakayanahalli
2005-10-10 14:44 ` [PATCH 6/9] Kprobes: Track kprobe on a per_cpu basis - sparc64 changes Ananth N Mavinakayanahalli
2005-10-10 14:45 ` [PATCH 7/9] Kprobes: Track kprobe on a per_cpu basis - x86_64 changes Ananth N Mavinakayanahalli
2005-10-10 14:47 ` [PATCH 8/9] Kprobes: Use RCU for (un)register synchronization - base changes Ananth N Mavinakayanahalli
2005-10-10 14:48 ` [PATCH 9/9] Kprobes: Use RCU for (un)register synchronization - arch changes Ananth N Mavinakayanahalli
2005-10-18 5:49 ` Paul E. McKenney
2005-10-18 14:45 ` Ananth N Mavinakayanahalli
2005-10-18 16:35 ` Paul E. McKenney [this message]
2005-10-18 5:44 ` [PATCH 8/9] Kprobes: Use RCU for (un)register synchronization - base changes Paul E. McKenney
2005-10-18 14:43 ` Ananth N Mavinakayanahalli
2005-10-18 16:31 ` Paul E. McKenney
2005-10-18 17:09 ` Ananth N Mavinakayanahalli
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