| Message ID | 20211015025847.17694-7-madvenka@linux.microsoft.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: Reorganize the unwinder and implement stack trace reliability checks | expand |
Hi, > -----Original Message----- > From: madvenka@linux.microsoft.com <madvenka@linux.microsoft.com> > Sent: Friday, October 15, 2021 11:59 AM > To: mark.rutland@arm.com; broonie@kernel.org; jpoimboe@redhat.com; ardb@kernel.org; Nobuta, Keiya/信田 圭哉 > <nobuta.keiya@fujitsu.com>; sjitindarsingh@gmail.com; catalin.marinas@arm.com; will@kernel.org; jmorris@namei.org; > linux-arm-kernel@lists.infradead.org; live-patching@vger.kernel.org; linux-kernel@vger.kernel.org; > madvenka@linux.microsoft.com > Subject: [PATCH v10 06/11] arm64: Make profile_pc() use arch_stack_walk() > > From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com> > > Currently, profile_pc() in ARM64 code walks the stack using > start_backtrace() and unwind_frame(). Make it use arch_stack_walk() instead. This makes maintenance easier. > > Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com> > --- > arch/arm64/kernel/time.c | 22 +++++++++++++--------- > 1 file changed, 13 insertions(+), 9 deletions(-) > > diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c index eebbc8d7123e..671b3038a772 100644 > --- a/arch/arm64/kernel/time.c > +++ b/arch/arm64/kernel/time.c > @@ -32,22 +32,26 @@ > #include <asm/stacktrace.h> > #include <asm/paravirt.h> > > +static bool profile_pc_cb(void *arg, unsigned long pc) { > + unsigned long *prof_pc = arg; > + > + if (in_lock_functions(pc)) > + return true; > + *prof_pc = pc; > + return false; > +} > + > unsigned long profile_pc(struct pt_regs *regs) { > - struct stackframe frame; > + unsigned long prof_pc = 0; > > if (!in_lock_functions(regs->pc)) > return regs->pc; > > - start_backtrace(&frame, regs->regs[29], regs->pc); > - > - do { > - int ret = unwind_frame(NULL, &frame); > - if (ret < 0) > - return 0; > - } while (in_lock_functions(frame.pc)); > + arch_stack_walk(profile_pc_cb, &prof_pc, current, regs); > > - return frame.pc; > + return prof_pc; > } > EXPORT_SYMBOL(profile_pc); > > -- > 2.25.1 I've got build error with CONFIG_ACPI=n: ==== arch/arm64/kernel/time.c: In function 'profile_pc': arch/arm64/kernel/time.c:52:2: error: implicit declaration of function 'arch_stack_walk' [-Werror=implicit-function-declaration] 52 | arch_stack_walk(profile_pc_cb, &prof_pc, current, regs); | ^~~~~~~~~~~~~~~ ==== I think it should include <linux/stacktrace.h> instead of <asm/stacktrace.h>. Thanks, Keiya
On Thu, Oct 14, 2021 at 09:58:42PM -0500, madvenka@linux.microsoft.com wrote: > From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com> > > Currently, profile_pc() in ARM64 code walks the stack using > start_backtrace() and unwind_frame(). Make it use arch_stack_walk() > instead. This makes maintenance easier. > > Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com> > --- > arch/arm64/kernel/time.c | 22 +++++++++++++--------- > 1 file changed, 13 insertions(+), 9 deletions(-) > > diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c > index eebbc8d7123e..671b3038a772 100644 > --- a/arch/arm64/kernel/time.c > +++ b/arch/arm64/kernel/time.c > @@ -32,22 +32,26 @@ > #include <asm/stacktrace.h> > #include <asm/paravirt.h> > > +static bool profile_pc_cb(void *arg, unsigned long pc) > +{ > + unsigned long *prof_pc = arg; > + > + if (in_lock_functions(pc)) > + return true; > + *prof_pc = pc; > + return false; > +} > + > unsigned long profile_pc(struct pt_regs *regs) > { > - struct stackframe frame; > + unsigned long prof_pc = 0; > > if (!in_lock_functions(regs->pc)) > return regs->pc; This can go -- the first call to profile_pc_cb() will use regs->pc. With that gone, and the include updates to use <linux/stacktrace.h>: Reviewed-by: Mark Rutland <mark.rutland@arm.com> Mark. > - start_backtrace(&frame, regs->regs[29], regs->pc); > - > - do { > - int ret = unwind_frame(NULL, &frame); > - if (ret < 0) > - return 0; > - } while (in_lock_functions(frame.pc)); > + arch_stack_walk(profile_pc_cb, &prof_pc, current, regs); > > - return frame.pc; > + return prof_pc; > } > EXPORT_SYMBOL(profile_pc); > > -- > 2.25.1 >
On 10/24/21 9:18 PM, nobuta.keiya@fujitsu.com wrote: > Hi, > >> -----Original Message----- >> From: madvenka@linux.microsoft.com <madvenka@linux.microsoft.com> >> Sent: Friday, October 15, 2021 11:59 AM >> To: mark.rutland@arm.com; broonie@kernel.org; jpoimboe@redhat.com; ardb@kernel.org; Nobuta, Keiya/信田 圭哉 >> <nobuta.keiya@fujitsu.com>; sjitindarsingh@gmail.com; catalin.marinas@arm.com; will@kernel.org; jmorris@namei.org; >> linux-arm-kernel@lists.infradead.org; live-patching@vger.kernel.org; linux-kernel@vger.kernel.org; >> madvenka@linux.microsoft.com >> Subject: [PATCH v10 06/11] arm64: Make profile_pc() use arch_stack_walk() >> >> From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com> >> >> Currently, profile_pc() in ARM64 code walks the stack using >> start_backtrace() and unwind_frame(). Make it use arch_stack_walk() instead. This makes maintenance easier. >> >> Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com> >> --- >> arch/arm64/kernel/time.c | 22 +++++++++++++--------- >> 1 file changed, 13 insertions(+), 9 deletions(-) >> >> diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c index eebbc8d7123e..671b3038a772 100644 >> --- a/arch/arm64/kernel/time.c >> +++ b/arch/arm64/kernel/time.c >> @@ -32,22 +32,26 @@ >> #include <asm/stacktrace.h> >> #include <asm/paravirt.h> >> >> +static bool profile_pc_cb(void *arg, unsigned long pc) { >> + unsigned long *prof_pc = arg; >> + >> + if (in_lock_functions(pc)) >> + return true; >> + *prof_pc = pc; >> + return false; >> +} >> + >> unsigned long profile_pc(struct pt_regs *regs) { >> - struct stackframe frame; >> + unsigned long prof_pc = 0; >> >> if (!in_lock_functions(regs->pc)) >> return regs->pc; >> >> - start_backtrace(&frame, regs->regs[29], regs->pc); >> - >> - do { >> - int ret = unwind_frame(NULL, &frame); >> - if (ret < 0) >> - return 0; >> - } while (in_lock_functions(frame.pc)); >> + arch_stack_walk(profile_pc_cb, &prof_pc, current, regs); >> >> - return frame.pc; >> + return prof_pc; >> } >> EXPORT_SYMBOL(profile_pc); >> >> -- >> 2.25.1 > > > I've got build error with CONFIG_ACPI=n: > ==== > arch/arm64/kernel/time.c: In function 'profile_pc': > arch/arm64/kernel/time.c:52:2: error: implicit declaration of function 'arch_stack_walk' [-Werror=implicit-function-declaration] > 52 | arch_stack_walk(profile_pc_cb, &prof_pc, current, regs); > | ^~~~~~~~~~~~~~~ > ==== > > I think it should include <linux/stacktrace.h> instead of <asm/stacktrace.h>. > OK. I will fix this. Thanks for catching this. Madhavan
On 10/27/21 8:32 AM, Mark Rutland wrote: > On Thu, Oct 14, 2021 at 09:58:42PM -0500, madvenka@linux.microsoft.com wrote: >> From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com> >> >> Currently, profile_pc() in ARM64 code walks the stack using >> start_backtrace() and unwind_frame(). Make it use arch_stack_walk() >> instead. This makes maintenance easier. >> >> Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com> >> --- >> arch/arm64/kernel/time.c | 22 +++++++++++++--------- >> 1 file changed, 13 insertions(+), 9 deletions(-) >> >> diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c >> index eebbc8d7123e..671b3038a772 100644 >> --- a/arch/arm64/kernel/time.c >> +++ b/arch/arm64/kernel/time.c >> @@ -32,22 +32,26 @@ >> #include <asm/stacktrace.h> >> #include <asm/paravirt.h> >> >> +static bool profile_pc_cb(void *arg, unsigned long pc) >> +{ >> + unsigned long *prof_pc = arg; >> + >> + if (in_lock_functions(pc)) >> + return true; >> + *prof_pc = pc; >> + return false; >> +} >> + >> unsigned long profile_pc(struct pt_regs *regs) >> { >> - struct stackframe frame; >> + unsigned long prof_pc = 0; >> >> if (!in_lock_functions(regs->pc)) >> return regs->pc; > > This can go -- the first call to profile_pc_cb() will use regs->pc. > Agreed. > With that gone, and the include updates to use <linux/stacktrace.h>: > > Reviewed-by: Mark Rutland <mark.rutland@arm.com> > I will make the two changes. Madhavan
diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c index eebbc8d7123e..671b3038a772 100644 --- a/arch/arm64/kernel/time.c +++ b/arch/arm64/kernel/time.c @@ -32,22 +32,26 @@ #include <asm/stacktrace.h> #include <asm/paravirt.h> +static bool profile_pc_cb(void *arg, unsigned long pc) +{ + unsigned long *prof_pc = arg; + + if (in_lock_functions(pc)) + return true; + *prof_pc = pc; + return false; +} + unsigned long profile_pc(struct pt_regs *regs) { - struct stackframe frame; + unsigned long prof_pc = 0; if (!in_lock_functions(regs->pc)) return regs->pc; - start_backtrace(&frame, regs->regs[29], regs->pc); - - do { - int ret = unwind_frame(NULL, &frame); - if (ret < 0) - return 0; - } while (in_lock_functions(frame.pc)); + arch_stack_walk(profile_pc_cb, &prof_pc, current, regs); - return frame.pc; + return prof_pc; } EXPORT_SYMBOL(profile_pc);