From: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
Mark Brown <broonie@kernel.org>,
Kalesh Singh <kaleshsingh@google.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Marc Zyngier <maz@kernel.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
Sandeepa Prabhu <sandeepa.s.prabhu@gmail.com>
Subject: [PATCH v2 1/3] arm64: Prohibit instrumentation on arch_stack_walk()
Date: Fri, 2 Dec 2022 11:18:33 +0900 [thread overview]
Message-ID: <166994751368.439920.3236636557520824664.stgit@devnote3> (raw)
In-Reply-To: <166994750386.439920.1754385804350980158.stgit@devnote3>
From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Mark arch_stack_walk() as noinstr instead of notrace and inline functions
called from arch_stack_walk() as __always_inline so that user does not
put any instrumentations on it, because this function can be used from
return_address() which is used by lockdep.
Without this, if the kernel built with CONFIG_LOCKDEP=y, just probing
arch_stack_walk() via <tracefs>/kprobe_events will crash the kernel on
arm64.
# echo p arch_stack_walk >> ${TRACEFS}/kprobe_events
# echo 1 > ${TRACEFS}/events/kprobes/enable
kprobes: Failed to recover from reentered kprobes.
kprobes: Dump kprobe:
.symbol_name = arch_stack_walk, .offset = 0, .addr = arch_stack_walk+0x0/0x1c0
------------[ cut here ]------------
kernel BUG at arch/arm64/kernel/probes/kprobes.c:241!
kprobes: Failed to recover from reentered kprobes.
kprobes: Dump kprobe:
.symbol_name = arch_stack_walk, .offset = 0, .addr = arch_stack_walk+0x0/0x1c0
------------[ cut here ]------------
kernel BUG at arch/arm64/kernel/probes/kprobes.c:241!
PREEMPT SMP
Modules linked in:
CPU: 0 PID: 17 Comm: migration/0 Tainted: G N 6.1.0-rc5+ #6
Hardware name: linux,dummy-virt (DT)
Stopper: 0x0 <- 0x0
pstate: 600003c5 (nZCv DAIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : kprobe_breakpoint_handler+0x178/0x17c
lr : kprobe_breakpoint_handler+0x178/0x17c
sp : ffff8000080d3090
x29: ffff8000080d3090 x28: ffff0df5845798c0 x27: ffffc4f59057a774
x26: ffff0df5ffbba770 x25: ffff0df58f420f18 x24: ffff49006f641000
x23: ffffc4f590579768 x22: ffff0df58f420f18 x21: ffff8000080d31c0
x20: ffffc4f590579768 x19: ffffc4f590579770 x18: 0000000000000006
x17: 5f6b636174735f68 x16: 637261203d207264 x15: 64612e202c30203d
x14: 2074657366666f2e x13: 30633178302f3078 x12: 302b6b6c61775f6b
x11: 636174735f686372 x10: ffffc4f590dc5bd8 x9 : ffffc4f58eb31958
x8 : 00000000ffffefff x7 : ffffc4f590dc5bd8 x6 : 80000000fffff000
x5 : 000000000000bff4 x4 : 0000000000000000 x3 : 0000000000000000
x2 : 0000000000000000 x1 : ffff0df5845798c0 x0 : 0000000000000064
Call trace:
kprobes: Failed to recover from reentered kprobes.
kprobes: Dump kprobe:
.symbol_name = arch_stack_walk, .offset = 0, .addr = arch_stack_walk+0x0/0x1c0
------------[ cut here ]------------
kernel BUG at arch/arm64/kernel/probes/kprobes.c:241!
Fixes: 39ef362d2d45 ("arm64: Make return_address() use arch_stack_walk()")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
Changes in v2:
- Use noinstr instead of NOKPROBE_SYMBOL()
- Use __always_inline because nokprobe_inline will be changed if
CONFIG_KPROBES=n.
- Fix indentation.
---
arch/arm64/kernel/stacktrace.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index 634279b3b03d..117e2c180f3c 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -23,8 +23,8 @@
*
* The regs must be on a stack currently owned by the calling task.
*/
-static inline void unwind_init_from_regs(struct unwind_state *state,
- struct pt_regs *regs)
+static __always_inline void unwind_init_from_regs(struct unwind_state *state,
+ struct pt_regs *regs)
{
unwind_init_common(state, current);
@@ -58,8 +58,8 @@ static __always_inline void unwind_init_from_caller(struct unwind_state *state)
* duration of the unwind, or the unwind will be bogus. It is never valid to
* call this for the current task.
*/
-static inline void unwind_init_from_task(struct unwind_state *state,
- struct task_struct *task)
+static __always_inline void unwind_init_from_task(struct unwind_state *state,
+ struct task_struct *task)
{
unwind_init_common(state, task);
@@ -186,7 +186,7 @@ void show_stack(struct task_struct *tsk, unsigned long *sp, const char *loglvl)
: stackinfo_get_unknown(); \
})
-noinline notrace void arch_stack_walk(stack_trace_consume_fn consume_entry,
+noinline noinstr void arch_stack_walk(stack_trace_consume_fn consume_entry,
void *cookie, struct task_struct *task,
struct pt_regs *regs)
{
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
WARNING: multiple messages have this Message-ID (diff)
From: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
Mark Brown <broonie@kernel.org>,
Kalesh Singh <kaleshsingh@google.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Marc Zyngier <maz@kernel.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
Sandeepa Prabhu <sandeepa.s.prabhu@gmail.com>
Subject: [PATCH v2 1/3] arm64: Prohibit instrumentation on arch_stack_walk()
Date: Fri, 2 Dec 2022 11:18:33 +0900 [thread overview]
Message-ID: <166994751368.439920.3236636557520824664.stgit@devnote3> (raw)
In-Reply-To: <166994750386.439920.1754385804350980158.stgit@devnote3>
From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Mark arch_stack_walk() as noinstr instead of notrace and inline functions
called from arch_stack_walk() as __always_inline so that user does not
put any instrumentations on it, because this function can be used from
return_address() which is used by lockdep.
Without this, if the kernel built with CONFIG_LOCKDEP=y, just probing
arch_stack_walk() via <tracefs>/kprobe_events will crash the kernel on
arm64.
# echo p arch_stack_walk >> ${TRACEFS}/kprobe_events
# echo 1 > ${TRACEFS}/events/kprobes/enable
kprobes: Failed to recover from reentered kprobes.
kprobes: Dump kprobe:
.symbol_name = arch_stack_walk, .offset = 0, .addr = arch_stack_walk+0x0/0x1c0
------------[ cut here ]------------
kernel BUG at arch/arm64/kernel/probes/kprobes.c:241!
kprobes: Failed to recover from reentered kprobes.
kprobes: Dump kprobe:
.symbol_name = arch_stack_walk, .offset = 0, .addr = arch_stack_walk+0x0/0x1c0
------------[ cut here ]------------
kernel BUG at arch/arm64/kernel/probes/kprobes.c:241!
PREEMPT SMP
Modules linked in:
CPU: 0 PID: 17 Comm: migration/0 Tainted: G N 6.1.0-rc5+ #6
Hardware name: linux,dummy-virt (DT)
Stopper: 0x0 <- 0x0
pstate: 600003c5 (nZCv DAIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : kprobe_breakpoint_handler+0x178/0x17c
lr : kprobe_breakpoint_handler+0x178/0x17c
sp : ffff8000080d3090
x29: ffff8000080d3090 x28: ffff0df5845798c0 x27: ffffc4f59057a774
x26: ffff0df5ffbba770 x25: ffff0df58f420f18 x24: ffff49006f641000
x23: ffffc4f590579768 x22: ffff0df58f420f18 x21: ffff8000080d31c0
x20: ffffc4f590579768 x19: ffffc4f590579770 x18: 0000000000000006
x17: 5f6b636174735f68 x16: 637261203d207264 x15: 64612e202c30203d
x14: 2074657366666f2e x13: 30633178302f3078 x12: 302b6b6c61775f6b
x11: 636174735f686372 x10: ffffc4f590dc5bd8 x9 : ffffc4f58eb31958
x8 : 00000000ffffefff x7 : ffffc4f590dc5bd8 x6 : 80000000fffff000
x5 : 000000000000bff4 x4 : 0000000000000000 x3 : 0000000000000000
x2 : 0000000000000000 x1 : ffff0df5845798c0 x0 : 0000000000000064
Call trace:
kprobes: Failed to recover from reentered kprobes.
kprobes: Dump kprobe:
.symbol_name = arch_stack_walk, .offset = 0, .addr = arch_stack_walk+0x0/0x1c0
------------[ cut here ]------------
kernel BUG at arch/arm64/kernel/probes/kprobes.c:241!
Fixes: 39ef362d2d45 ("arm64: Make return_address() use arch_stack_walk()")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
Changes in v2:
- Use noinstr instead of NOKPROBE_SYMBOL()
- Use __always_inline because nokprobe_inline will be changed if
CONFIG_KPROBES=n.
- Fix indentation.
---
arch/arm64/kernel/stacktrace.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index 634279b3b03d..117e2c180f3c 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -23,8 +23,8 @@
*
* The regs must be on a stack currently owned by the calling task.
*/
-static inline void unwind_init_from_regs(struct unwind_state *state,
- struct pt_regs *regs)
+static __always_inline void unwind_init_from_regs(struct unwind_state *state,
+ struct pt_regs *regs)
{
unwind_init_common(state, current);
@@ -58,8 +58,8 @@ static __always_inline void unwind_init_from_caller(struct unwind_state *state)
* duration of the unwind, or the unwind will be bogus. It is never valid to
* call this for the current task.
*/
-static inline void unwind_init_from_task(struct unwind_state *state,
- struct task_struct *task)
+static __always_inline void unwind_init_from_task(struct unwind_state *state,
+ struct task_struct *task)
{
unwind_init_common(state, task);
@@ -186,7 +186,7 @@ void show_stack(struct task_struct *tsk, unsigned long *sp, const char *loglvl)
: stackinfo_get_unknown(); \
})
-noinline notrace void arch_stack_walk(stack_trace_consume_fn consume_entry,
+noinline noinstr void arch_stack_walk(stack_trace_consume_fn consume_entry,
void *cookie, struct task_struct *task,
struct pt_regs *regs)
{
next prev parent reply other threads:[~2022-12-02 2:19 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-02 2:18 [PATCH v2 0/3] arm64: kprobes: Fix bugs in kprobes for arm64 Masami Hiramatsu (Google)
2022-12-02 2:18 ` Masami Hiramatsu (Google)
2022-12-02 2:18 ` Masami Hiramatsu (Google) [this message]
2022-12-02 2:18 ` [PATCH v2 1/3] arm64: Prohibit instrumentation on arch_stack_walk() Masami Hiramatsu (Google)
2022-12-02 13:17 ` Mark Rutland
2022-12-02 13:17 ` Mark Rutland
2022-12-06 0:41 ` Masami Hiramatsu
2022-12-06 0:41 ` Masami Hiramatsu
2022-12-09 11:16 ` Mark Rutland
2022-12-09 11:16 ` Mark Rutland
2022-12-11 3:30 ` Masami Hiramatsu
2022-12-11 3:30 ` Masami Hiramatsu
2022-12-02 2:18 ` [PATCH v2 2/3] arm64: kprobes: Let arch do_page_fault() fix up page fault in user handler Masami Hiramatsu (Google)
2022-12-02 2:18 ` Masami Hiramatsu (Google)
2022-12-02 2:18 ` [PATCH v2 3/3] arm64: kprobes: Return DBG_HOOK_ERROR if kprobes can not handle a BRK Masami Hiramatsu (Google)
2022-12-02 2:18 ` Masami Hiramatsu (Google)
2022-12-05 15:43 ` [PATCH v2 0/3] arm64: kprobes: Fix bugs in kprobes for arm64 Will Deacon
2022-12-05 15:43 ` Will Deacon
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