* [PATCH 0/4] powerpc: build out kprobes blacklist
@ 2017-04-25 16:34 Naveen N. Rao
2017-04-25 16:34 ` [PATCH 1/4] powerpc/kprobes: cleanup system_call_common and blacklist it from kprobes Naveen N. Rao
` (4 more replies)
0 siblings, 5 replies; 7+ messages in thread
From: Naveen N. Rao @ 2017-04-25 16:34 UTC (permalink / raw)
To: Michael Ellerman
Cc: Anton Blanchard, Ananth N Mavinakayanahalli, Masami Hiramatsu,
linuxppc-dev
This is the second in the series of patches to build out an appropriate
kprobes blacklist. This series blacklists system_call() and functions
involved when handling the trap itself. Not everything is covered, but
this is the first set of functions that I have tested with. More
patches to follow once I expand my tests.
I have converted many labels into private -- these are labels that I
felt are not necessary to read stack traces. If any of those are
important to have, please let me know.
- Naveen
Naveen N. Rao (4):
powerpc/kprobes: cleanup system_call_common and blacklist it from
kprobes
powerpc/kprobes: un-blacklist system_call() from kprobes
powerpc/kprobes: blacklist functions invoked on a trap
powerpc/kprobes: blacklist functions involved when returning from
exception
arch/powerpc/kernel/entry_64.S | 94 +++++++++++++++++++-----------------
arch/powerpc/kernel/exceptions-64s.S | 1 +
arch/powerpc/kernel/time.c | 3 ++
arch/powerpc/kernel/traps.c | 3 ++
arch/powerpc/platforms/pseries/dtl.c | 2 +
5 files changed, 60 insertions(+), 43 deletions(-)
--
2.12.1
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH 1/4] powerpc/kprobes: cleanup system_call_common and blacklist it from kprobes
2017-04-25 16:34 [PATCH 0/4] powerpc: build out kprobes blacklist Naveen N. Rao
@ 2017-04-25 16:34 ` Naveen N. Rao
2017-04-25 16:34 ` [PATCH 2/4] powerpc/kprobes: un-blacklist system_call() " Naveen N. Rao
` (3 subsequent siblings)
4 siblings, 0 replies; 7+ messages in thread
From: Naveen N. Rao @ 2017-04-25 16:34 UTC (permalink / raw)
To: Michael Ellerman
Cc: Anton Blanchard, Ananth N Mavinakayanahalli, Masami Hiramatsu,
linuxppc-dev
Convert some of the labels into private labels and blacklist
system_call_common() and system_call() from kprobes. We can't take a
trap at parts of these functions as either MSR_RI is unset or the
kernel stack pointer is not yet setup.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
---
arch/powerpc/kernel/entry_64.S | 25 +++++++++++++------------
1 file changed, 13 insertions(+), 12 deletions(-)
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 9b541d22595a..380361c0bb6a 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -52,12 +52,11 @@ exception_marker:
.section ".text"
.align 7
- .globl system_call_common
-system_call_common:
+_GLOBAL(system_call_common)
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
BEGIN_FTR_SECTION
extrdi. r10, r12, 1, (63-MSR_TS_T_LG) /* transaction active? */
- bne tabort_syscall
+ bne .Ltabort_syscall
END_FTR_SECTION_IFSET(CPU_FTR_TM)
#endif
andi. r10,r12,MSR_PR
@@ -152,9 +151,9 @@ END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR)
CURRENT_THREAD_INFO(r11, r1)
ld r10,TI_FLAGS(r11)
andi. r11,r10,_TIF_SYSCALL_DOTRACE
- bne syscall_dotrace /* does not return */
+ bne .Lsyscall_dotrace /* does not return */
cmpldi 0,r0,NR_syscalls
- bge- syscall_enosys
+ bge- .Lsyscall_enosys
system_call: /* label this so stack traces look sane */
/*
@@ -208,7 +207,7 @@ system_call: /* label this so stack traces look sane */
ld r9,TI_FLAGS(r12)
li r11,-MAX_ERRNO
andi. r0,r9,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)
- bne- syscall_exit_work
+ bne- .Lsyscall_exit_work
andi. r0,r8,MSR_FP
beq 2f
@@ -232,7 +231,7 @@ system_call: /* label this so stack traces look sane */
3: cmpld r3,r11
ld r5,_CCR(r1)
- bge- syscall_error
+ bge- .Lsyscall_error
.Lsyscall_error_cont:
ld r7,_NIP(r1)
BEGIN_FTR_SECTION
@@ -258,14 +257,14 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
RFI
b . /* prevent speculative execution */
-syscall_error:
+.Lsyscall_error:
oris r5,r5,0x1000 /* Set SO bit in CR */
neg r3,r3
std r5,_CCR(r1)
b .Lsyscall_error_cont
/* Traced system call support */
-syscall_dotrace:
+.Lsyscall_dotrace:
bl save_nvgprs
addi r3,r1,STACK_FRAME_OVERHEAD
bl do_syscall_trace_enter
@@ -298,11 +297,11 @@ syscall_dotrace:
b .Lsyscall_exit
-syscall_enosys:
+.Lsyscall_enosys:
li r3,-ENOSYS
b .Lsyscall_exit
-syscall_exit_work:
+.Lsyscall_exit_work:
#ifdef CONFIG_PPC_BOOK3S
li r10,MSR_RI
mtmsrd r10,1 /* Restore RI */
@@ -362,7 +361,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
b ret_from_except
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
-tabort_syscall:
+.Ltabort_syscall:
/* Firstly we need to enable TM in the kernel */
mfmsr r10
li r9, 1
@@ -388,6 +387,8 @@ tabort_syscall:
rfid
b . /* prevent speculative execution */
#endif
+_ASM_NOKPROBE_SYMBOL(system_call_common);
+_ASM_NOKPROBE_SYMBOL(system_call);
/* Save non-volatile GPRs, if not already saved. */
_GLOBAL(save_nvgprs)
--
2.12.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH 2/4] powerpc/kprobes: un-blacklist system_call() from kprobes
2017-04-25 16:34 [PATCH 0/4] powerpc: build out kprobes blacklist Naveen N. Rao
2017-04-25 16:34 ` [PATCH 1/4] powerpc/kprobes: cleanup system_call_common and blacklist it from kprobes Naveen N. Rao
@ 2017-04-25 16:34 ` Naveen N. Rao
2017-04-25 16:34 ` [PATCH 3/4] powerpc/kprobes: blacklist functions invoked on a trap Naveen N. Rao
` (2 subsequent siblings)
4 siblings, 0 replies; 7+ messages in thread
From: Naveen N. Rao @ 2017-04-25 16:34 UTC (permalink / raw)
To: Michael Ellerman
Cc: Anton Blanchard, Ananth N Mavinakayanahalli, Masami Hiramatsu,
linuxppc-dev
It is actually safe to probe system_call() in entry_64.S, but only till
.Lsyscall_exit. To allow this, convert .Lsyscall_exit to a non-local
symbol __system_call() and blacklist that symbol, rather than
system_call().
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
---
arch/powerpc/kernel/entry_64.S | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 380361c0bb6a..e030ce34dd66 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -176,7 +176,7 @@ system_call: /* label this so stack traces look sane */
mtctr r12
bctrl /* Call handler */
-.Lsyscall_exit:
+__system_call:
std r3,RESULT(r1)
CURRENT_THREAD_INFO(r12, r1)
@@ -294,12 +294,12 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
blt+ system_call
/* Return code is already in r3 thanks to do_syscall_trace_enter() */
- b .Lsyscall_exit
+ b __system_call
.Lsyscall_enosys:
li r3,-ENOSYS
- b .Lsyscall_exit
+ b __system_call
.Lsyscall_exit_work:
#ifdef CONFIG_PPC_BOOK3S
@@ -388,7 +388,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
b . /* prevent speculative execution */
#endif
_ASM_NOKPROBE_SYMBOL(system_call_common);
-_ASM_NOKPROBE_SYMBOL(system_call);
+_ASM_NOKPROBE_SYMBOL(__system_call);
/* Save non-volatile GPRs, if not already saved. */
_GLOBAL(save_nvgprs)
@@ -413,38 +413,38 @@ _GLOBAL(save_nvgprs)
_GLOBAL(ppc_fork)
bl save_nvgprs
bl sys_fork
- b .Lsyscall_exit
+ b __system_call
_GLOBAL(ppc_vfork)
bl save_nvgprs
bl sys_vfork
- b .Lsyscall_exit
+ b __system_call
_GLOBAL(ppc_clone)
bl save_nvgprs
bl sys_clone
- b .Lsyscall_exit
+ b __system_call
_GLOBAL(ppc32_swapcontext)
bl save_nvgprs
bl compat_sys_swapcontext
- b .Lsyscall_exit
+ b __system_call
_GLOBAL(ppc64_swapcontext)
bl save_nvgprs
bl sys_swapcontext
- b .Lsyscall_exit
+ b __system_call
_GLOBAL(ppc_switch_endian)
bl save_nvgprs
bl sys_switch_endian
- b .Lsyscall_exit
+ b __system_call
_GLOBAL(ret_from_fork)
bl schedule_tail
REST_NVGPRS(r1)
li r3,0
- b .Lsyscall_exit
+ b __system_call
_GLOBAL(ret_from_kernel_thread)
bl schedule_tail
@@ -456,7 +456,7 @@ _GLOBAL(ret_from_kernel_thread)
#endif
blrl
li r3,0
- b .Lsyscall_exit
+ b __system_call
/*
* This routine switches between two different tasks. The process
--
2.12.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH 3/4] powerpc/kprobes: blacklist functions invoked on a trap
2017-04-25 16:34 [PATCH 0/4] powerpc: build out kprobes blacklist Naveen N. Rao
2017-04-25 16:34 ` [PATCH 1/4] powerpc/kprobes: cleanup system_call_common and blacklist it from kprobes Naveen N. Rao
2017-04-25 16:34 ` [PATCH 2/4] powerpc/kprobes: un-blacklist system_call() " Naveen N. Rao
@ 2017-04-25 16:34 ` Naveen N. Rao
2017-04-25 16:34 ` [PATCH 4/4] powerpc/kprobes: blacklist functions involved when returning from exception Naveen N. Rao
2017-04-27 2:24 ` [PATCH 0/4] powerpc: build out kprobes blacklist Masami Hiramatsu
4 siblings, 0 replies; 7+ messages in thread
From: Naveen N. Rao @ 2017-04-25 16:34 UTC (permalink / raw)
To: Michael Ellerman
Cc: Anton Blanchard, Ananth N Mavinakayanahalli, Masami Hiramatsu,
linuxppc-dev
Blacklist all functions invoked when we get a trap, through to the time
we invoke the kprobe handler.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
---
arch/powerpc/kernel/entry_64.S | 1 +
arch/powerpc/kernel/exceptions-64s.S | 1 +
arch/powerpc/kernel/time.c | 3 +++
arch/powerpc/kernel/traps.c | 2 ++
arch/powerpc/platforms/pseries/dtl.c | 2 ++
5 files changed, 9 insertions(+)
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index e030ce34dd66..22aaa377149f 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -399,6 +399,7 @@ _GLOBAL(save_nvgprs)
clrrdi r0,r11,1
std r0,_TRAP(r1)
blr
+_ASM_NOKPROBE_SYMBOL(save_nvgprs);
/*
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 28f8d7bed6b1..aff23b2288f2 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -1534,6 +1534,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
1: addi r3,r1,STACK_FRAME_OVERHEAD
bl kernel_bad_stack
b 1b
+_ASM_NOKPROBE_SYMBOL(bad_stack);
/*
* Called from arch_local_irq_enable when an interrupt needs
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 07b90725855e..afdec3c00738 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -59,6 +59,7 @@
#include <linux/suspend.h>
#include <linux/rtc.h>
#include <linux/sched/cputime.h>
+#include <linux/kprobes.h>
#include <asm/trace.h>
#include <asm/io.h>
@@ -236,6 +237,7 @@ static u64 scan_dispatch_log(u64 stop_tb)
local_paca->dtl_curr = dtl;
return stolen;
}
+NOKPROBE_SYMBOL(scan_dispatch_log);
/*
* Accumulate stolen time by scanning the dispatch trace log.
@@ -263,6 +265,7 @@ void accumulate_stolen_time(void)
local_paca->soft_enabled = save_soft_enabled;
}
+NOKPROBE_SYMBOL(accumulate_stolen_time);
static inline u64 calculate_stolen_time(u64 stop_tb)
{
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 76f6045b021b..ece130515cd0 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -237,6 +237,7 @@ void die(const char *str, struct pt_regs *regs, long err)
err = 0;
oops_end(flags, regs, err);
}
+NOKPROBE_SYMBOL(die);
void user_single_step_siginfo(struct task_struct *tsk,
struct pt_regs *regs, siginfo_t *info)
@@ -1981,6 +1982,7 @@ void kernel_bad_stack(struct pt_regs *regs)
regs->gpr[1], regs->nip);
die("Bad kernel stack pointer", regs, SIGABRT);
}
+NOKPROBE_SYMBOL(kernel_bad_stack);
void __init trap_init(void)
{
diff --git a/arch/powerpc/platforms/pseries/dtl.c b/arch/powerpc/platforms/pseries/dtl.c
index 18014cdeb590..03d333ff7867 100644
--- a/arch/powerpc/platforms/pseries/dtl.c
+++ b/arch/powerpc/platforms/pseries/dtl.c
@@ -29,6 +29,7 @@
#include <asm/debugfs.h>
#include <asm/plpar_wrappers.h>
#include <asm/machdep.h>
+#include <linux/kprobes.h>
struct dtl {
struct dtl_entry *buf;
@@ -97,6 +98,7 @@ static void consume_dtle(struct dtl_entry *dtle, u64 index)
smp_wmb();
++dtlr->write_index;
}
+NOKPROBE_SYMBOL(consume_dtle);
static int dtl_start(struct dtl *dtl)
{
--
2.12.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH 4/4] powerpc/kprobes: blacklist functions involved when returning from exception
2017-04-25 16:34 [PATCH 0/4] powerpc: build out kprobes blacklist Naveen N. Rao
` (2 preceding siblings ...)
2017-04-25 16:34 ` [PATCH 3/4] powerpc/kprobes: blacklist functions invoked on a trap Naveen N. Rao
@ 2017-04-25 16:34 ` Naveen N. Rao
2017-04-27 2:24 ` [PATCH 0/4] powerpc: build out kprobes blacklist Masami Hiramatsu
4 siblings, 0 replies; 7+ messages in thread
From: Naveen N. Rao @ 2017-04-25 16:34 UTC (permalink / raw)
To: Michael Ellerman
Cc: Anton Blanchard, Ananth N Mavinakayanahalli, Masami Hiramatsu,
linuxppc-dev
Blacklist all functions involved when we return from a trap. We:
- convert some of the labels into private labels,
- remove the duplicate 'restore' label, and
- blacklist most functions involved during returning from a trap.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
---
arch/powerpc/kernel/entry_64.S | 46 ++++++++++++++++++++++++------------------
arch/powerpc/kernel/traps.c | 1 +
2 files changed, 27 insertions(+), 20 deletions(-)
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 22aaa377149f..e7e05eb590a5 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -184,7 +184,7 @@ __system_call:
#ifdef CONFIG_PPC_BOOK3S
/* No MSR:RI on BookE */
andi. r10,r8,MSR_RI
- beq- unrecov_restore
+ beq- .Lunrecov_restore
#endif
/*
* Disable interrupts so current_thread_info()->flags can't change,
@@ -643,18 +643,18 @@ _GLOBAL(ret_from_except_lite)
* Use the internal debug mode bit to do this.
*/
andis. r0,r3,DBCR0_IDM@h
- beq restore
+ beq fast_exc_return_irq
mfmsr r0
rlwinm r0,r0,0,~MSR_DE /* Clear MSR.DE */
mtmsr r0
mtspr SPRN_DBCR0,r3
li r10, -1
mtspr SPRN_DBSR,r10
- b restore
+ b fast_exc_return_irq
#else
addi r3,r1,STACK_FRAME_OVERHEAD
bl restore_math
- b restore
+ b fast_exc_return_irq
#endif
1: andi. r0,r4,_TIF_NEED_RESCHED
beq 2f
@@ -667,7 +667,7 @@ _GLOBAL(ret_from_except_lite)
bne 3f /* only restore TM if nothing else to do */
addi r3,r1,STACK_FRAME_OVERHEAD
bl restore_tm_state
- b restore
+ b fast_exc_return_irq
3:
#endif
bl save_nvgprs
@@ -719,14 +719,14 @@ resume_kernel:
#ifdef CONFIG_PREEMPT
/* Check if we need to preempt */
andi. r0,r4,_TIF_NEED_RESCHED
- beq+ restore
+ beq+ fast_exc_return_irq
/* Check that preempt_count() == 0 and interrupts are enabled */
lwz r8,TI_PREEMPT(r9)
cmpwi cr1,r8,0
ld r0,SOFTE(r1)
cmpdi r0,0
crandc eq,cr1*4+eq,eq
- bne restore
+ bne fast_exc_return_irq
/*
* Here we are preempting the current task. We want to make
@@ -757,7 +757,6 @@ resume_kernel:
.globl fast_exc_return_irq
fast_exc_return_irq:
-restore:
/*
* This is the main kernel exit path. First we check if we
* are about to re-enable interrupts
@@ -765,11 +764,11 @@ restore:
ld r5,SOFTE(r1)
lbz r6,PACASOFTIRQEN(r13)
cmpwi cr0,r5,0
- beq restore_irq_off
+ beq .Lrestore_irq_off
/* We are enabling, were we already enabled ? Yes, just return */
cmpwi cr0,r6,1
- beq cr0,do_restore
+ beq cr0,.Ldo_restore
/*
* We are about to soft-enable interrupts (we are hard disabled
@@ -778,14 +777,14 @@ restore:
*/
lbz r0,PACAIRQHAPPENED(r13)
cmpwi cr0,r0,0
- bne- restore_check_irq_replay
+ bne- .Lrestore_check_irq_replay
/*
* Get here when nothing happened while soft-disabled, just
* soft-enable and move-on. We will hard-enable as a side
* effect of rfi
*/
-restore_no_replay:
+.Lrestore_no_replay:
TRACE_ENABLE_INTS
li r0,1
stb r0,PACASOFTIRQEN(r13);
@@ -793,7 +792,7 @@ restore_no_replay:
/*
* Final return path. BookE is handled in a different file
*/
-do_restore:
+.Ldo_restore:
#ifdef CONFIG_PPC_BOOK3E
b exception_return_book3e
#else
@@ -827,7 +826,7 @@ fast_exception_return:
REST_8GPRS(5, r1)
andi. r0,r3,MSR_RI
- beq- unrecov_restore
+ beq- .Lunrecov_restore
/* Load PPR from thread struct before we clear MSR:RI */
BEGIN_FTR_SECTION
@@ -885,7 +884,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
* make sure that in this case, we also clear PACA_IRQ_HARD_DIS
* or that bit can get out of sync and bad things will happen
*/
-restore_irq_off:
+.Lrestore_irq_off:
ld r3,_MSR(r1)
lbz r7,PACAIRQHAPPENED(r13)
andi. r0,r3,MSR_EE
@@ -895,13 +894,13 @@ restore_irq_off:
1: li r0,0
stb r0,PACASOFTIRQEN(r13);
TRACE_DISABLE_INTS
- b do_restore
+ b .Ldo_restore
/*
* Something did happen, check if a re-emit is needed
* (this also clears paca->irq_happened)
*/
-restore_check_irq_replay:
+.Lrestore_check_irq_replay:
/* XXX: We could implement a fast path here where we check
* for irq_happened being just 0x01, in which case we can
* clear it and return. That means that we would potentially
@@ -911,7 +910,7 @@ restore_check_irq_replay:
*/
bl __check_irq_replay
cmpwi cr0,r3,0
- beq restore_no_replay
+ beq .Lrestore_no_replay
/*
* We need to re-emit an interrupt. We do so by re-using our
@@ -960,10 +959,17 @@ restore_check_irq_replay:
#endif /* CONFIG_PPC_DOORBELL */
1: b ret_from_except /* What else to do here ? */
-unrecov_restore:
+.Lunrecov_restore:
addi r3,r1,STACK_FRAME_OVERHEAD
bl unrecoverable_exception
- b unrecov_restore
+ b .Lunrecov_restore
+
+_ASM_NOKPROBE_SYMBOL(ret_from_except);
+_ASM_NOKPROBE_SYMBOL(ret_from_except_lite);
+_ASM_NOKPROBE_SYMBOL(resume_kernel);
+_ASM_NOKPROBE_SYMBOL(fast_exc_return_irq);
+_ASM_NOKPROBE_SYMBOL(fast_exception_return);
+
#ifdef CONFIG_PPC_RTAS
/*
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index ece130515cd0..8ce51787b2ba 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -1952,6 +1952,7 @@ void unrecoverable_exception(struct pt_regs *regs)
regs->trap, regs->nip);
die("Unrecoverable exception", regs, SIGABRT);
}
+NOKPROBE_SYMBOL(unrecoverable_exception);
#if defined(CONFIG_BOOKE_WDT) || defined(CONFIG_40x)
/*
--
2.12.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH 0/4] powerpc: build out kprobes blacklist
2017-04-25 16:34 [PATCH 0/4] powerpc: build out kprobes blacklist Naveen N. Rao
` (3 preceding siblings ...)
2017-04-25 16:34 ` [PATCH 4/4] powerpc/kprobes: blacklist functions involved when returning from exception Naveen N. Rao
@ 2017-04-27 2:24 ` Masami Hiramatsu
2017-04-27 6:16 ` Naveen N. Rao
4 siblings, 1 reply; 7+ messages in thread
From: Masami Hiramatsu @ 2017-04-27 2:24 UTC (permalink / raw)
To: Naveen N. Rao
Cc: Michael Ellerman, Anton Blanchard, Ananth N Mavinakayanahalli,
Masami Hiramatsu, linuxppc-dev
Hello Naveen,
On Tue, 25 Apr 2017 22:04:05 +0530
"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> wrote:
> This is the second in the series of patches to build out an appropriate
> kprobes blacklist. This series blacklists system_call() and functions
> involved when handling the trap itself. Not everything is covered, but
> this is the first set of functions that I have tested with. More
> patches to follow once I expand my tests.
OK, btw, have you tested to put kprobes on these functions and
saw kernel panic happened?
> I have converted many labels into private -- these are labels that I
> felt are not necessary to read stack traces. If any of those are
> important to have, please let me know.
At least from the viewpoint of kprobe-blacklist macros, it seems
good to me :)
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
for this series.
Thank you,
>
> - Naveen
>
> Naveen N. Rao (4):
> powerpc/kprobes: cleanup system_call_common and blacklist it from
> kprobes
> powerpc/kprobes: un-blacklist system_call() from kprobes
> powerpc/kprobes: blacklist functions invoked on a trap
> powerpc/kprobes: blacklist functions involved when returning from
> exception
>
> arch/powerpc/kernel/entry_64.S | 94 +++++++++++++++++++-----------------
> arch/powerpc/kernel/exceptions-64s.S | 1 +
> arch/powerpc/kernel/time.c | 3 ++
> arch/powerpc/kernel/traps.c | 3 ++
> arch/powerpc/platforms/pseries/dtl.c | 2 +
> 5 files changed, 60 insertions(+), 43 deletions(-)
>
> --
> 2.12.1
>
--
Masami Hiramatsu <mhiramat@kernel.org>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 0/4] powerpc: build out kprobes blacklist
2017-04-27 2:24 ` [PATCH 0/4] powerpc: build out kprobes blacklist Masami Hiramatsu
@ 2017-04-27 6:16 ` Naveen N. Rao
0 siblings, 0 replies; 7+ messages in thread
From: Naveen N. Rao @ 2017-04-27 6:16 UTC (permalink / raw)
To: Masami Hiramatsu
Cc: Michael Ellerman, Anton Blanchard, Ananth N Mavinakayanahalli,
linuxppc-dev
On 2017/04/27 11:24AM, Masami Hiramatsu wrote:
> Hello Naveen,
>
> On Tue, 25 Apr 2017 22:04:05 +0530
> "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> wrote:
>
> > This is the second in the series of patches to build out an appropriate
> > kprobes blacklist. This series blacklists system_call() and functions
> > involved when handling the trap itself. Not everything is covered, but
> > this is the first set of functions that I have tested with. More
> > patches to follow once I expand my tests.
>
> OK, btw, have you tested to put kprobes on these functions and
> saw kernel panic happened?
Thanks for the question! I re-checked and I just realized I hadn't
tested the PAPR case (stolen time accounting). On testing, I just found
that those functions are not a problem since they are only invoked when
we are coming in from user-space and not when we take a trap in-kernel.
I will re-spin patch 3/4. Other functions have been tested to cause
issues with kprobes.
There are still a few more functions involved (especially with
CONFIG_PREEMPT) where I couldn't reproduce an issue, so I haven't
included those in this series. I am continuing to test this further and
will post subsequent patches once I work out which other functions are
problematic.
>
> > I have converted many labels into private -- these are labels that I
> > felt are not necessary to read stack traces. If any of those are
> > important to have, please let me know.
>
> At least from the viewpoint of kprobe-blacklist macros, it seems
> good to me :)
>
> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
>
> for this series.
>
> Thank you,
Thanks for the review!
- Naveen
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2017-04-27 6:17 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-04-25 16:34 [PATCH 0/4] powerpc: build out kprobes blacklist Naveen N. Rao
2017-04-25 16:34 ` [PATCH 1/4] powerpc/kprobes: cleanup system_call_common and blacklist it from kprobes Naveen N. Rao
2017-04-25 16:34 ` [PATCH 2/4] powerpc/kprobes: un-blacklist system_call() " Naveen N. Rao
2017-04-25 16:34 ` [PATCH 3/4] powerpc/kprobes: blacklist functions invoked on a trap Naveen N. Rao
2017-04-25 16:34 ` [PATCH 4/4] powerpc/kprobes: blacklist functions involved when returning from exception Naveen N. Rao
2017-04-27 2:24 ` [PATCH 0/4] powerpc: build out kprobes blacklist Masami Hiramatsu
2017-04-27 6:16 ` Naveen N. Rao
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