* [RFC PATCH -tip v5 07/27] powerpc/kprobes: Remove jprobe powerpc implementation
[not found] <152812730943.10068.5166429445118734697.stgit@devbox>
@ 2018-06-04 15:51 ` Masami Hiramatsu
2018-06-07 11:31 ` Naveen N. Rao
2018-06-04 15:57 ` [RFC PATCH -tip v5 18/27] powerpc/kprobes: Don't call the ->break_handler() in arm kprobes code Masami Hiramatsu
2018-06-04 16:00 ` [RFC PATCH -tip v5 24/27] bpf: error-inject: kprobes: Clear current_kprobe and enable preempt in kprobe Masami Hiramatsu
2 siblings, 1 reply; 10+ messages in thread
From: Masami Hiramatsu @ 2018-06-04 15:51 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar
Cc: Masami Hiramatsu, Ingo Molnar, H . Peter Anvin, linux-kernel,
Ananth N Mavinakayanahalli, Andrew Morton, Steven Rostedt,
linux-arch, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, Naveen N. Rao, linuxppc-dev
Remove arch dependent setjump/longjump functions
and unused fields in kprobe_ctlblk for jprobes
from arch/powerpc. This also reverts commits
related __is_active_jprobe() function.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
---
arch/powerpc/include/asm/kprobes.h | 2 -
arch/powerpc/kernel/kprobes-ftrace.c | 15 -------
arch/powerpc/kernel/kprobes.c | 54 ------------------------
arch/powerpc/kernel/trace/ftrace_64_mprofile.S | 39 ++---------------
4 files changed, 5 insertions(+), 105 deletions(-)
diff --git a/arch/powerpc/include/asm/kprobes.h b/arch/powerpc/include/asm/kprobes.h
index 9f3be5c8a4a3..674036db558b 100644
--- a/arch/powerpc/include/asm/kprobes.h
+++ b/arch/powerpc/include/asm/kprobes.h
@@ -88,7 +88,6 @@ struct prev_kprobe {
struct kprobe_ctlblk {
unsigned long kprobe_status;
unsigned long kprobe_saved_msr;
- struct pt_regs jprobe_saved_regs;
struct prev_kprobe prev_kprobe;
};
@@ -104,7 +103,6 @@ extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr);
extern int kprobe_handler(struct pt_regs *regs);
extern int kprobe_post_handler(struct pt_regs *regs);
#ifdef CONFIG_KPROBES_ON_FTRACE
-extern int __is_active_jprobe(unsigned long addr);
extern int skip_singlestep(struct kprobe *p, struct pt_regs *regs,
struct kprobe_ctlblk *kcb);
#else
diff --git a/arch/powerpc/kernel/kprobes-ftrace.c b/arch/powerpc/kernel/kprobes-ftrace.c
index 7a1f99f1b47f..1b316331c2d9 100644
--- a/arch/powerpc/kernel/kprobes-ftrace.c
+++ b/arch/powerpc/kernel/kprobes-ftrace.c
@@ -25,21 +25,6 @@
#include <linux/preempt.h>
#include <linux/ftrace.h>
-/*
- * This is called from ftrace code after invoking registered handlers to
- * disambiguate regs->nip changes done by jprobes and livepatch. We check if
- * there is an active jprobe at the provided address (mcount location).
- */
-int __is_active_jprobe(unsigned long addr)
-{
- if (!preemptible()) {
- struct kprobe *p = raw_cpu_read(current_kprobe);
- return (p && (unsigned long)p->addr == addr) ? 1 : 0;
- }
-
- return 0;
-}
-
static nokprobe_inline
int __skip_singlestep(struct kprobe *p, struct pt_regs *regs,
struct kprobe_ctlblk *kcb, unsigned long orig_nip)
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index e4c5bf33970b..600678fce0a8 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -611,60 +611,6 @@ unsigned long arch_deref_entry_point(void *entry)
}
NOKPROBE_SYMBOL(arch_deref_entry_point);
-int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct jprobe *jp = container_of(p, struct jprobe, kp);
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs));
-
- /* setup return addr to the jprobe handler routine */
- regs->nip = arch_deref_entry_point(jp->entry);
-#ifdef PPC64_ELF_ABI_v2
- regs->gpr[12] = (unsigned long)jp->entry;
-#elif defined(PPC64_ELF_ABI_v1)
- regs->gpr[2] = (unsigned long)(((func_descr_t *)jp->entry)->toc);
-#endif
-
- /*
- * jprobes use jprobe_return() which skips the normal return
- * path of the function, and this messes up the accounting of the
- * function graph tracer.
- *
- * Pause function graph tracing while performing the jprobe function.
- */
- pause_graph_tracing();
-
- return 1;
-}
-NOKPROBE_SYMBOL(setjmp_pre_handler);
-
-void __used jprobe_return(void)
-{
- asm volatile("jprobe_return_trap:\n"
- "trap\n"
- ::: "memory");
-}
-NOKPROBE_SYMBOL(jprobe_return);
-
-int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- if (regs->nip != ppc_kallsyms_lookup_name("jprobe_return_trap")) {
- pr_debug("longjmp_break_handler NIP (0x%lx) does not match jprobe_return_trap (0x%lx)\n",
- regs->nip, ppc_kallsyms_lookup_name("jprobe_return_trap"));
- return 0;
- }
-
- memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs));
- /* It's OK to start function graph tracing again */
- unpause_graph_tracing();
- preempt_enable_no_resched();
- return 1;
-}
-NOKPROBE_SYMBOL(longjmp_break_handler);
-
static struct kprobe trampoline_p = {
.addr = (kprobe_opcode_t *) &kretprobe_trampoline,
.pre_handler = trampoline_probe_handler
diff --git a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
index 3f3e81852422..4e84a713e80a 100644
--- a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
+++ b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
@@ -99,39 +99,13 @@ ftrace_call:
bl ftrace_stub
nop
- /* Load the possibly modified NIP */
- ld r15, _NIP(r1)
-
+ /* Load ctr with the possibly modified NIP */
+ ld r3, _NIP(r1)
+ mtctr r3
#ifdef CONFIG_LIVEPATCH
- cmpd r14, r15 /* has NIP been altered? */
+ cmpd r14, r3 /* has NIP been altered? */
#endif
-#if defined(CONFIG_LIVEPATCH) && defined(CONFIG_KPROBES_ON_FTRACE)
- /* NIP has not been altered, skip over further checks */
- beq 1f
-
- /* Check if there is an active jprobe on us */
- subi r3, r14, 4
- bl __is_active_jprobe
- nop
-
- /*
- * If r3 == 1, then this is a kprobe/jprobe.
- * else, this is livepatched function.
- *
- * The conditional branch for livepatch_handler below will use the
- * result of this comparison. For kprobe/jprobe, we just need to branch to
- * the new NIP, not call livepatch_handler. The branch below is bne, so we
- * want CR0[EQ] to be true if this is a kprobe/jprobe. Which means we want
- * CR0[EQ] = (r3 == 1).
- */
- cmpdi r3, 1
-1:
-#endif
-
- /* Load CTR with the possibly modified NIP */
- mtctr r15
-
/* Restore gprs */
REST_GPR(0,r1)
REST_10GPRS(2,r1)
@@ -149,10 +123,7 @@ ftrace_call:
addi r1, r1, SWITCH_FRAME_SIZE
#ifdef CONFIG_LIVEPATCH
- /*
- * Based on the cmpd or cmpdi above, if the NIP was altered and we're
- * not on a kprobe/jprobe, then handle livepatch.
- */
+ /* Based on the cmpd above, if the NIP was altered handle livepatch */
bne- livepatch_handler
#endif
^ permalink raw reply related [flat|nested] 10+ messages in thread* [RFC PATCH -tip v5 18/27] powerpc/kprobes: Don't call the ->break_handler() in arm kprobes code
[not found] <152812730943.10068.5166429445118734697.stgit@devbox>
2018-06-04 15:51 ` [RFC PATCH -tip v5 07/27] powerpc/kprobes: Remove jprobe powerpc implementation Masami Hiramatsu
@ 2018-06-04 15:57 ` Masami Hiramatsu
2018-06-07 11:37 ` Naveen N. Rao
2018-06-04 16:00 ` [RFC PATCH -tip v5 24/27] bpf: error-inject: kprobes: Clear current_kprobe and enable preempt in kprobe Masami Hiramatsu
2 siblings, 1 reply; 10+ messages in thread
From: Masami Hiramatsu @ 2018-06-04 15:57 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar
Cc: Masami Hiramatsu, Ingo Molnar, H . Peter Anvin, linux-kernel,
Ananth N Mavinakayanahalli, Andrew Morton, Steven Rostedt,
linux-arch, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, Naveen N. Rao, linuxppc-dev
Don't call the ->break_handler() from the arm kprobes code,
because it was only used by jprobes which got removed.
This also makes skip_singlestep() a static function since
only ftrace-kprobe.c is using this function.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
---
arch/powerpc/include/asm/kprobes.h | 10 ----------
arch/powerpc/kernel/kprobes-ftrace.c | 16 +++-------------
arch/powerpc/kernel/kprobes.c | 31 +++++++++++--------------------
3 files changed, 14 insertions(+), 43 deletions(-)
diff --git a/arch/powerpc/include/asm/kprobes.h b/arch/powerpc/include/asm/kprobes.h
index 674036db558b..785c464b6588 100644
--- a/arch/powerpc/include/asm/kprobes.h
+++ b/arch/powerpc/include/asm/kprobes.h
@@ -102,16 +102,6 @@ extern int kprobe_exceptions_notify(struct notifier_block *self,
extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr);
extern int kprobe_handler(struct pt_regs *regs);
extern int kprobe_post_handler(struct pt_regs *regs);
-#ifdef CONFIG_KPROBES_ON_FTRACE
-extern int skip_singlestep(struct kprobe *p, struct pt_regs *regs,
- struct kprobe_ctlblk *kcb);
-#else
-static inline int skip_singlestep(struct kprobe *p, struct pt_regs *regs,
- struct kprobe_ctlblk *kcb)
-{
- return 0;
-}
-#endif
#else
static inline int kprobe_handler(struct pt_regs *regs) { return 0; }
static inline int kprobe_post_handler(struct pt_regs *regs) { return 0; }
diff --git a/arch/powerpc/kernel/kprobes-ftrace.c b/arch/powerpc/kernel/kprobes-ftrace.c
index 1b316331c2d9..3869b0e5d5c7 100644
--- a/arch/powerpc/kernel/kprobes-ftrace.c
+++ b/arch/powerpc/kernel/kprobes-ftrace.c
@@ -26,8 +26,8 @@
#include <linux/ftrace.h>
static nokprobe_inline
-int __skip_singlestep(struct kprobe *p, struct pt_regs *regs,
- struct kprobe_ctlblk *kcb, unsigned long orig_nip)
+int skip_singlestep(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb, unsigned long orig_nip)
{
/*
* Emulate singlestep (and also recover regs->nip)
@@ -44,16 +44,6 @@ int __skip_singlestep(struct kprobe *p, struct pt_regs *regs,
return 1;
}
-int skip_singlestep(struct kprobe *p, struct pt_regs *regs,
- struct kprobe_ctlblk *kcb)
-{
- if (kprobe_ftrace(p))
- return __skip_singlestep(p, regs, kcb, 0);
- else
- return 0;
-}
-NOKPROBE_SYMBOL(skip_singlestep);
-
/* Ftrace callback handler for kprobes */
void kprobe_ftrace_handler(unsigned long nip, unsigned long parent_nip,
struct ftrace_ops *ops, struct pt_regs *regs)
@@ -82,7 +72,7 @@ void kprobe_ftrace_handler(unsigned long nip, unsigned long parent_nip,
__this_cpu_write(current_kprobe, p);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
if (!p->pre_handler || !p->pre_handler(p, regs))
- __skip_singlestep(p, regs, kcb, orig_nip);
+ skip_singlestep(p, regs, kcb, orig_nip);
else {
/*
* If pre_handler returns !0, it sets regs->nip and
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 600678fce0a8..f06747e2e70d 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -317,25 +317,17 @@ int kprobe_handler(struct pt_regs *regs)
}
prepare_singlestep(p, regs);
return 1;
- } else {
- if (*addr != BREAKPOINT_INSTRUCTION) {
- /* If trap variant, then it belongs not to us */
- kprobe_opcode_t cur_insn = *addr;
- if (is_trap(cur_insn))
- goto no_kprobe;
- /* The breakpoint instruction was removed by
- * another cpu right after we hit, no further
- * handling of this interrupt is appropriate
- */
- ret = 1;
+ } else if (*addr != BREAKPOINT_INSTRUCTION) {
+ /* If trap variant, then it belongs not to us */
+ kprobe_opcode_t cur_insn = *addr;
+
+ if (is_trap(cur_insn))
goto no_kprobe;
- }
- p = __this_cpu_read(current_kprobe);
- if (p->break_handler && p->break_handler(p, regs)) {
- if (!skip_singlestep(p, regs, kcb))
- goto ss_probe;
- ret = 1;
- }
+ /* The breakpoint instruction was removed by
+ * another cpu right after we hit, no further
+ * handling of this interrupt is appropriate
+ */
+ ret = 1;
}
goto no_kprobe;
}
@@ -350,7 +342,7 @@ int kprobe_handler(struct pt_regs *regs)
*/
kprobe_opcode_t cur_insn = *addr;
if (is_trap(cur_insn))
- goto no_kprobe;
+ goto no_kprobe;
/*
* The breakpoint instruction was removed right
* after we hit it. Another cpu has removed
@@ -370,7 +362,6 @@ int kprobe_handler(struct pt_regs *regs)
/* handler has already set things up, so skip ss setup */
return 1;
-ss_probe:
if (p->ainsn.boostable >= 0) {
ret = try_to_emulate(p, regs);
^ permalink raw reply related [flat|nested] 10+ messages in thread* [RFC PATCH -tip v5 24/27] bpf: error-inject: kprobes: Clear current_kprobe and enable preempt in kprobe
[not found] <152812730943.10068.5166429445118734697.stgit@devbox>
2018-06-04 15:51 ` [RFC PATCH -tip v5 07/27] powerpc/kprobes: Remove jprobe powerpc implementation Masami Hiramatsu
2018-06-04 15:57 ` [RFC PATCH -tip v5 18/27] powerpc/kprobes: Don't call the ->break_handler() in arm kprobes code Masami Hiramatsu
@ 2018-06-04 16:00 ` Masami Hiramatsu
2018-06-07 11:42 ` Naveen N. Rao
2 siblings, 1 reply; 10+ messages in thread
From: Masami Hiramatsu @ 2018-06-04 16:00 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar
Cc: Masami Hiramatsu, Ingo Molnar, H . Peter Anvin, linux-kernel,
Ananth N Mavinakayanahalli, Andrew Morton, Steven Rostedt,
linux-arch, Vineet Gupta, Russell King, Catalin Marinas,
Will Deacon, Tony Luck, Fenghua Yu, Ralf Baechle, James Hogan,
Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
Martin Schwidefsky, Heiko Carstens, Yoshinori Sato, Rich Felker,
David S. Miller, Naveen N. Rao, Josef Bacik, Alexei Starovoitov,
x86, linux-snps-arc, linux-arm-kernel, linux-ia64, linux-mips,
linuxppc-dev, linux-s390, linux-sh, sparclinux
Clear current_kprobe and enable preemption in kprobe
even if pre_handler returns !0.
This simplifies function override using kprobes.
Jprobe used to require to keep the preemption disabled and
keep current_kprobe until it returned to original function
entry. For this reason kprobe_int3_handler() and similar
arch dependent kprobe handers checks pre_handler result
and exit without enabling preemption if the result is !0.
After removing the jprobe, Kprobes does not need to
keep preempt disabled even if user handler returns !0
anymore.
But since the function override handler in error-inject
and bpf is also returns !0 if it overrides a function,
to balancing the preempt count, it enables preemption
and reset current kprobe by itself.
That is a bad design that is very buggy. This fixes
such unbalanced preempt-count and current_kprobes setting
in kprobes, bpf and error-inject.
Note: for powerpc and x86, this removes all preempt_disable
from kprobe_ftrace_handler because ftrace callbacks are
called under preempt disabled.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc: Josef Bacik <jbacik@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: x86@kernel.org
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: sparclinux@vger.kernel.org
---
Changes in v5:
- Fix kprobe_ftrace_handler in arch/powerpc too.
---
arch/arc/kernel/kprobes.c | 5 +++--
arch/arm/probes/kprobes/core.c | 10 +++++-----
arch/arm64/kernel/probes/kprobes.c | 10 +++++-----
arch/ia64/kernel/kprobes.c | 13 ++++---------
arch/mips/kernel/kprobes.c | 4 ++--
arch/powerpc/kernel/kprobes-ftrace.c | 15 ++++++---------
arch/powerpc/kernel/kprobes.c | 7 +++++--
arch/s390/kernel/kprobes.c | 7 ++++---
arch/sh/kernel/kprobes.c | 7 ++++---
arch/sparc/kernel/kprobes.c | 7 ++++---
arch/x86/kernel/kprobes/core.c | 4 ++++
arch/x86/kernel/kprobes/ftrace.c | 15 ++++++++-------
kernel/fail_function.c | 3 ---
kernel/trace/trace_kprobe.c | 11 +++--------
14 files changed, 57 insertions(+), 61 deletions(-)
diff --git a/arch/arc/kernel/kprobes.c b/arch/arc/kernel/kprobes.c
index 465365696c91..df35d4c0b0b8 100644
--- a/arch/arc/kernel/kprobes.c
+++ b/arch/arc/kernel/kprobes.c
@@ -231,6 +231,9 @@ int __kprobes arc_kprobe_handler(unsigned long addr, struct pt_regs *regs)
if (!p->pre_handler || !p->pre_handler(p, regs)) {
setup_singlestep(p, regs);
kcb->kprobe_status = KPROBE_HIT_SS;
+ } else {
+ reset_current_kprobe();
+ preempt_enable_no_resched();
}
return 1;
@@ -442,9 +445,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,
kretprobe_assert(ri, orig_ret_address, trampoline_address);
regs->ret = orig_ret_address;
- reset_current_kprobe();
kretprobe_hash_unlock(current, &flags);
- preempt_enable_no_resched();
hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c
index 3192350f389d..8d37601fdb20 100644
--- a/arch/arm/probes/kprobes/core.c
+++ b/arch/arm/probes/kprobes/core.c
@@ -300,10 +300,10 @@ void __kprobes kprobe_handler(struct pt_regs *regs)
/*
* If we have no pre-handler or it returned 0, we
- * continue with normal processing. If we have a
- * pre-handler and it returned non-zero, it prepped
- * for calling the break_handler below on re-entry,
- * so get out doing nothing more here.
+ * continue with normal processing. If we have a
+ * pre-handler and it returned non-zero, it will
+ * modify the execution path and no need to single
+ * stepping. Let's just reset current kprobe and exit.
*/
if (!p->pre_handler || !p->pre_handler(p, regs)) {
kcb->kprobe_status = KPROBE_HIT_SS;
@@ -312,8 +312,8 @@ void __kprobes kprobe_handler(struct pt_regs *regs)
kcb->kprobe_status = KPROBE_HIT_SSDONE;
p->post_handler(p, regs, 0);
}
- reset_current_kprobe();
}
+ reset_current_kprobe();
}
} else {
/*
diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
index 076c3c0775a6..5daf3d721cb7 100644
--- a/arch/arm64/kernel/probes/kprobes.c
+++ b/arch/arm64/kernel/probes/kprobes.c
@@ -395,9 +395,9 @@ static void __kprobes kprobe_handler(struct pt_regs *regs)
/*
* If we have no pre-handler or it returned 0, we
* continue with normal processing. If we have a
- * pre-handler and it returned non-zero, it prepped
- * for calling the break_handler below on re-entry,
- * so get out doing nothing more here.
+ * pre-handler and it returned non-zero, it will
+ * modify the execution path and no need to single
+ * stepping. Let's just reset current kprobe and exit.
*
* pre_handler can hit a breakpoint and can step thru
* before return, keep PSTATE D-flag enabled until
@@ -405,8 +405,8 @@ static void __kprobes kprobe_handler(struct pt_regs *regs)
*/
if (!p->pre_handler || !p->pre_handler(p, regs)) {
setup_singlestep(p, regs, kcb, 0);
- return;
- }
+ } else
+ reset_current_kprobe();
}
}
/*
diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index 74c8524e6309..aa41bd5cf9b7 100644
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -478,12 +478,9 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
*/
break;
}
-
kretprobe_assert(ri, orig_ret_address, trampoline_address);
- reset_current_kprobe();
kretprobe_hash_unlock(current, &flags);
- preempt_enable_no_resched();
hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
@@ -851,13 +848,11 @@ static int __kprobes pre_kprobes_handler(struct die_args *args)
set_current_kprobe(p, kcb);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
- if (p->pre_handler && p->pre_handler(p, regs))
- /*
- * Our pre-handler is specifically requesting that we just
- * do a return. This is used for both the jprobe pre-handler
- * and the kretprobe trampoline
- */
+ if (p->pre_handler && p->pre_handler(p, regs)) {
+ reset_current_kprobe();
+ preempt_enable_no_resched();
return 1;
+ }
#if !defined(CONFIG_PREEMPT)
if (p->ainsn.inst_flag == INST_FLAG_BOOSTABLE && !p->post_handler) {
diff --git a/arch/mips/kernel/kprobes.c b/arch/mips/kernel/kprobes.c
index 7fd277bc59b9..54cd675c5d1d 100644
--- a/arch/mips/kernel/kprobes.c
+++ b/arch/mips/kernel/kprobes.c
@@ -358,6 +358,8 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
if (p->pre_handler && p->pre_handler(p, regs)) {
/* handler has already set things up, so skip ss setup */
+ reset_current_kprobe();
+ preempt_enable_no_resched();
return 1;
}
@@ -543,9 +545,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,
kretprobe_assert(ri, orig_ret_address, trampoline_address);
instruction_pointer(regs) = orig_ret_address;
- reset_current_kprobe();
kretprobe_hash_unlock(current, &flags);
- preempt_enable_no_resched();
hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
diff --git a/arch/powerpc/kernel/kprobes-ftrace.c b/arch/powerpc/kernel/kprobes-ftrace.c
index 3869b0e5d5c7..c80c35d1e26e 100644
--- a/arch/powerpc/kernel/kprobes-ftrace.c
+++ b/arch/powerpc/kernel/kprobes-ftrace.c
@@ -51,11 +51,9 @@ void kprobe_ftrace_handler(unsigned long nip, unsigned long parent_nip,
struct kprobe *p;
struct kprobe_ctlblk *kcb;
- preempt_disable();
-
p = get_kprobe((kprobe_opcode_t *)nip);
if (unlikely(!p) || kprobe_disabled(p))
- goto end;
+ return;
kcb = get_kprobe_ctlblk();
if (kprobe_running()) {
@@ -75,15 +73,14 @@ void kprobe_ftrace_handler(unsigned long nip, unsigned long parent_nip,
skip_singlestep(p, regs, kcb, orig_nip);
else {
/*
- * If pre_handler returns !0, it sets regs->nip and
- * resets current kprobe. In this case, we should not
- * re-enable preemption.
+ * If pre_handler returns !0, this handler
+ * modifies regs->ip and goes back to there
+ * directly without single stepping.
+ * So let's just clear current kprobe.
*/
- return;
+ __this_cpu_write(current_kprobe, NULL);
}
}
-end:
- preempt_enable_no_resched();
}
NOKPROBE_SYMBOL(kprobe_ftrace_handler);
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index f06747e2e70d..5c60bb0f927f 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -358,9 +358,12 @@ int kprobe_handler(struct pt_regs *regs)
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
set_current_kprobe(p, regs, kcb);
- if (p->pre_handler && p->pre_handler(p, regs))
- /* handler has already set things up, so skip ss setup */
+ if (p->pre_handler && p->pre_handler(p, regs)) {
+ /* handler changed execution path, so skip ss setup */
+ reset_current_kprobe();
+ preempt_enable_no_resched();
return 1;
+ }
if (p->ainsn.boostable >= 0) {
ret = try_to_emulate(p, regs);
diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index 3e34018960b5..7c0a095e9c5f 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -326,8 +326,11 @@ static int kprobe_handler(struct pt_regs *regs)
*/
push_kprobe(kcb, p);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
- if (p->pre_handler && p->pre_handler(p, regs))
+ if (p->pre_handler && p->pre_handler(p, regs)) {
+ pop_kprobe(kcb);
+ preempt_enable_no_resched();
return 1;
+ }
kcb->kprobe_status = KPROBE_HIT_SS;
}
enable_singlestep(kcb, regs, (unsigned long) p->ainsn.insn);
@@ -431,9 +434,7 @@ static int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
regs->psw.addr = orig_ret_address;
- pop_kprobe(get_kprobe_ctlblk());
kretprobe_hash_unlock(current, &flags);
- preempt_enable_no_resched();
hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
diff --git a/arch/sh/kernel/kprobes.c b/arch/sh/kernel/kprobes.c
index 4fafe0cd12c6..241e903dd3ee 100644
--- a/arch/sh/kernel/kprobes.c
+++ b/arch/sh/kernel/kprobes.c
@@ -272,9 +272,12 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
set_current_kprobe(p, regs, kcb);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
- if (p->pre_handler && p->pre_handler(p, regs))
+ if (p->pre_handler && p->pre_handler(p, regs)) {
/* handler has already set things up, so skip ss setup */
+ reset_current_kprobe();
+ preempt_enable_no_resched();
return 1;
+ }
prepare_singlestep(p, regs);
kcb->kprobe_status = KPROBE_HIT_SS;
@@ -352,8 +355,6 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
regs->pc = orig_ret_address;
kretprobe_hash_unlock(current, &flags);
- preempt_enable_no_resched();
-
hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
kfree(ri);
diff --git a/arch/sparc/kernel/kprobes.c b/arch/sparc/kernel/kprobes.c
index c684c96ef2e9..dfbca2470536 100644
--- a/arch/sparc/kernel/kprobes.c
+++ b/arch/sparc/kernel/kprobes.c
@@ -175,8 +175,11 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
set_current_kprobe(p, regs, kcb);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
- if (p->pre_handler && p->pre_handler(p, regs))
+ if (p->pre_handler && p->pre_handler(p, regs)) {
+ reset_current_kprobe();
+ preempt_enable_no_resched();
return 1;
+ }
prepare_singlestep(p, regs, kcb);
kcb->kprobe_status = KPROBE_HIT_SS;
@@ -508,9 +511,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,
regs->tpc = orig_ret_address;
regs->tnpc = orig_ret_address + 4;
- reset_current_kprobe();
kretprobe_hash_unlock(current, &flags);
- preempt_enable_no_resched();
hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 0ac16a0d93e5..814e26b7c8a2 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -694,6 +694,10 @@ int kprobe_int3_handler(struct pt_regs *regs)
*/
if (!p->pre_handler || !p->pre_handler(p, regs))
setup_singlestep(p, regs, kcb, 0);
+ else {
+ reset_current_kprobe();
+ preempt_enable_no_resched();
+ }
return 1;
}
} else if (*addr != BREAKPOINT_INSTRUCTION) {
diff --git a/arch/x86/kernel/kprobes/ftrace.c b/arch/x86/kernel/kprobes/ftrace.c
index c8696f2a583f..310ef737b9d4 100644
--- a/arch/x86/kernel/kprobes/ftrace.c
+++ b/arch/x86/kernel/kprobes/ftrace.c
@@ -63,18 +63,19 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
/* Kprobe handler expects regs->ip = ip + 1 as breakpoint hit */
regs->ip = ip + sizeof(kprobe_opcode_t);
- /* To emulate trap based kprobes, preempt_disable here */
- preempt_disable();
__this_cpu_write(current_kprobe, p);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
if (!p->pre_handler || !p->pre_handler(p, regs)) {
skip_singlestep(p, regs, kcb, orig_ip);
- preempt_enable_no_resched();
+ } else {
+ /*
+ * If pre_handler returns !0, this handler
+ * modifies regs->ip and goes back to there
+ * directly without single stepping.
+ * So let's just clear current kprobe.
+ */
+ __this_cpu_write(current_kprobe, NULL);
}
- /*
- * If pre_handler returns !0, it sets regs->ip and
- * resets current kprobe, and keep preempt count +1.
- */
}
}
NOKPROBE_SYMBOL(kprobe_ftrace_handler);
diff --git a/kernel/fail_function.c b/kernel/fail_function.c
index 1d5632d8bbcc..b090688df94f 100644
--- a/kernel/fail_function.c
+++ b/kernel/fail_function.c
@@ -184,9 +184,6 @@ static int fei_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
if (should_fail(&fei_fault_attr, 1)) {
regs_set_return_value(regs, attr->retval);
override_function_with_return(regs);
- /* Kprobe specific fixup */
- reset_current_kprobe();
- preempt_enable_no_resched();
return 1;
}
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 02aed76e0978..b65cd6834450 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1217,16 +1217,11 @@ kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
/*
* We need to check and see if we modified the pc of the
- * pt_regs, and if so clear the kprobe and return 1 so that we
- * don't do the single stepping.
- * The ftrace kprobe handler leaves it up to us to re-enable
- * preemption here before returning if we've modified the ip.
+ * pt_regs, and if so return 1 so that we don't do the
+ * single stepping.
*/
- if (orig_ip != instruction_pointer(regs)) {
- reset_current_kprobe();
- preempt_enable_no_resched();
+ if (orig_ip != instruction_pointer(regs))
return 1;
- }
if (!ret)
return 0;
}
^ permalink raw reply related [flat|nested] 10+ messages in thread