* [RFC PATCH -tip v5 08/27] ia64: kprobes: Remove jprobe implementation
[not found] <152812730943.10068.5166429445118734697.stgit@devbox>
@ 2018-06-04 15:52 ` Masami Hiramatsu
2018-06-04 15:57 ` [RFC PATCH -tip v5 19/27] ia64: kprobes: Don't call the ->break_handler() in ia64 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 kpr Masami Hiramatsu
2 siblings, 0 replies; 4+ messages in thread
From: Masami Hiramatsu @ 2018-06-04 15:52 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, Tony Luck, Fenghua Yu, linux-ia64
Remove arch dependent setjump/longjump functions
and unused fields in kprobe_ctlblk for jprobes
from arch/ia64.
Note that since ia64 jprobes code a bit different
from other arch, this keeps __IA64_BREAK_JPROBE
for checking break_handler. It will be removed
with break_handler() call afterwards.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: linux-ia64@vger.kernel.org
---
arch/ia64/include/asm/kprobes.h | 2 -
arch/ia64/kernel/Makefile | 2 -
arch/ia64/kernel/jprobes.S | 90 ---------------------------------------
arch/ia64/kernel/kprobes.c | 70 ------------------------------
4 files changed, 1 insertion(+), 163 deletions(-)
delete mode 100644 arch/ia64/kernel/jprobes.S
diff --git a/arch/ia64/include/asm/kprobes.h b/arch/ia64/include/asm/kprobes.h
index 0302b3664789..580356a2eea6 100644
--- a/arch/ia64/include/asm/kprobes.h
+++ b/arch/ia64/include/asm/kprobes.h
@@ -82,8 +82,6 @@ struct prev_kprobe {
#define ARCH_PREV_KPROBE_SZ 2
struct kprobe_ctlblk {
unsigned long kprobe_status;
- struct pt_regs jprobe_saved_regs;
- unsigned long jprobes_saved_stacked_regs[MAX_PARAM_RSE_SIZE];
unsigned long *bsp;
unsigned long cfm;
atomic_t prev_kprobe_index;
diff --git a/arch/ia64/kernel/Makefile b/arch/ia64/kernel/Makefile
index 498f3da3f225..d0c0ccdd656a 100644
--- a/arch/ia64/kernel/Makefile
+++ b/arch/ia64/kernel/Makefile
@@ -25,7 +25,7 @@ obj-$(CONFIG_NUMA) += numa.o
obj-$(CONFIG_PERFMON) += perfmon_default_smpl.o
obj-$(CONFIG_IA64_CYCLONE) += cyclone.o
obj-$(CONFIG_IA64_MCA_RECOVERY) += mca_recovery.o
-obj-$(CONFIG_KPROBES) += kprobes.o jprobes.o
+obj-$(CONFIG_KPROBES) += kprobes.o
obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o
obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o crash.o
obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
diff --git a/arch/ia64/kernel/jprobes.S b/arch/ia64/kernel/jprobes.S
deleted file mode 100644
index f69389c7be1d..000000000000
--- a/arch/ia64/kernel/jprobes.S
+++ /dev/null
@@ -1,90 +0,0 @@
-/*
- * Jprobe specific operations
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
- * Copyright (C) Intel Corporation, 2005
- *
- * 2005-May Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
- * <anil.s.keshavamurthy@intel.com> initial implementation
- *
- * Jprobes (a.k.a. "jump probes" which is built on-top of kprobes) allow a
- * probe to be inserted into the beginning of a function call. The fundamental
- * difference between a jprobe and a kprobe is the jprobe handler is executed
- * in the same context as the target function, while the kprobe handlers
- * are executed in interrupt context.
- *
- * For jprobes we initially gain control by placing a break point in the
- * first instruction of the targeted function. When we catch that specific
- * break, we:
- * * set the return address to our jprobe_inst_return() function
- * * jump to the jprobe handler function
- *
- * Since we fixed up the return address, the jprobe handler will return to our
- * jprobe_inst_return() function, giving us control again. At this point we
- * are back in the parents frame marker, so we do yet another call to our
- * jprobe_break() function to fix up the frame marker as it would normally
- * exist in the target function.
- *
- * Our jprobe_return function then transfers control back to kprobes.c by
- * executing a break instruction using one of our reserved numbers. When we
- * catch that break in kprobes.c, we continue like we do for a normal kprobe
- * by single stepping the emulated instruction, and then returning execution
- * to the correct location.
- */
-#include <asm/asmmacro.h>
-#include <asm/break.h>
-
- /*
- * void jprobe_break(void)
- */
- .section .kprobes.text, "ax"
-ENTRY(jprobe_break)
- break.m __IA64_BREAK_JPROBE
-END(jprobe_break)
-
- /*
- * void jprobe_inst_return(void)
- */
-GLOBAL_ENTRY(jprobe_inst_return)
- br.call.sptk.many b0=jprobe_break
-END(jprobe_inst_return)
-
-GLOBAL_ENTRY(invalidate_stacked_regs)
- movl r16=invalidate_restore_cfm
- ;;
- mov b6=r16
- ;;
- br.ret.sptk.many b6
- ;;
-invalidate_restore_cfm:
- mov r16=ar.rsc
- ;;
- mov ar.rsc=r0
- ;;
- loadrs
- ;;
- mov ar.rsc=r16
- ;;
- br.cond.sptk.many rp
-END(invalidate_stacked_regs)
-
-GLOBAL_ENTRY(flush_register_stack)
- // flush dirty regs to backing store (must be first in insn group)
- flushrs
- ;;
- br.ret.sptk.many rp
-END(flush_register_stack)
-
diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index f5f3a5e6fcd1..823e4bd03a18 100644
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -35,8 +35,6 @@
#include <asm/sections.h>
#include <asm/exception.h>
-extern void jprobe_inst_return(void);
-
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
@@ -1040,74 +1038,6 @@ unsigned long arch_deref_entry_point(void *entry)
return ((struct fnptr *)entry)->ip;
}
-int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct jprobe *jp = container_of(p, struct jprobe, kp);
- unsigned long addr = arch_deref_entry_point(jp->entry);
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- struct param_bsp_cfm pa;
- int bytes;
-
- /*
- * Callee owns the argument space and could overwrite it, eg
- * tail call optimization. So to be absolutely safe
- * we save the argument space before transferring the control
- * to instrumented jprobe function which runs in
- * the process context
- */
- pa.ip = regs->cr_iip;
- unw_init_running(ia64_get_bsp_cfm, &pa);
- bytes = (char *)ia64_rse_skip_regs(pa.bsp, pa.cfm & 0x3f)
- - (char *)pa.bsp;
- memcpy( kcb->jprobes_saved_stacked_regs,
- pa.bsp,
- bytes );
- kcb->bsp = pa.bsp;
- kcb->cfm = pa.cfm;
-
- /* save architectural state */
- kcb->jprobe_saved_regs = *regs;
-
- /* after rfi, execute the jprobe instrumented function */
- regs->cr_iip = addr & ~0xFULL;
- ia64_psr(regs)->ri = addr & 0xf;
- regs->r1 = ((struct fnptr *)(jp->entry))->gp;
-
- /*
- * fix the return address to our jprobe_inst_return() function
- * in the jprobes.S file
- */
- regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip;
-
- return 1;
-}
-
-/* ia64 does not need this */
-void __kprobes jprobe_return(void)
-{
-}
-
-int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- int bytes;
-
- /* restoring architectural state */
- *regs = kcb->jprobe_saved_regs;
-
- /* restoring the original argument space */
- flush_register_stack();
- bytes = (char *)ia64_rse_skip_regs(kcb->bsp, kcb->cfm & 0x3f)
- - (char *)kcb->bsp;
- memcpy( kcb->bsp,
- kcb->jprobes_saved_stacked_regs,
- bytes );
- invalidate_stacked_regs();
-
- preempt_enable_no_resched();
- return 1;
-}
-
static struct kprobe trampoline_p = {
.pre_handler = trampoline_probe_handler
};
^ permalink raw reply related [flat|nested] 4+ messages in thread* [RFC PATCH -tip v5 24/27] bpf: error-inject: kprobes: Clear current_kprobe and enable preempt in kpr
[not found] <152812730943.10068.5166429445118734697.stgit@devbox>
2018-06-04 15:52 ` [RFC PATCH -tip v5 08/27] ia64: kprobes: Remove jprobe implementation Masami Hiramatsu
2018-06-04 15:57 ` [RFC PATCH -tip v5 19/27] ia64: kprobes: Don't call the ->break_handler() in ia64 kprobes code Masami Hiramatsu
@ 2018-06-04 16:00 ` Masami Hiramatsu
2018-06-07 11:54 ` [RFC PATCH -tip v5 24/27] bpf: error-inject: kprobes: Clear current_kprobe and enable preempt in Naveen N. Rao
2 siblings, 1 reply; 4+ 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
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] 4+ messages in thread