From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com> To: Suraj Jitindar Singh <sjitindarsingh@gmail.com> Cc: poimboe@redhat.com, peterz@infradead.org, chenzhongjin@huawei.com, mark.rutland@arm.com, broonie@kernel.org, nobuta.keiya@fujitsu.com, catalin.marinas@arm.com, will@kernel.org, jamorris@linux.microsoft.com, linux-arm-kernel@lists.infradead.org, live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH v3 19/22] arm64: unwinder: Add a reliability check in the unwinder based on ORC Date: Mon, 6 Mar 2023 10:52:09 -0600 [thread overview] Message-ID: <56308235-3893-75ac-a19f-497cc203c520@linux.microsoft.com> (raw) In-Reply-To: <88ab8c8348373e5c7c90c985dd92b5e06f32b16b.camel@gmail.com> On 2/22/23 22:07, Suraj Jitindar Singh wrote: > On Thu, 2023-02-02 at 01:40 -0600, madvenka@linux.microsoft.com wrote: >> From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com> >> >> Introduce a reliability flag in struct unwind_state. This will be set >> to >> false if the PC does not have a valid ORC or if the frame pointer >> computed >> from the ORC does not match the actual frame pointer. >> >> Now that the unwinder can validate the frame pointer, introduce >> arch_stack_walk_reliable(). >> >> Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com >>> >> --- >> arch/arm64/include/asm/stacktrace/common.h | 15 ++ >> arch/arm64/kernel/stacktrace.c | 167 >> ++++++++++++++++++++- >> 2 files changed, 175 insertions(+), 7 deletions(-) >> > > [snip] > >> -static void notrace unwind(struct unwind_state *state, >> +static int notrace unwind(struct unwind_state *state, bool >> need_reliable, >> stack_trace_consume_fn consume_entry, void >> *cookie) >> { >> - while (1) { >> - int ret; >> + int ret = 0; >> >> + while (1) { >> + if (need_reliable && !state->reliable) >> + return -EINVAL; >> if (!consume_entry(cookie, state->pc)) >> break; >> ret = unwind_next(state); >> + if (need_reliable && !ret) >> + unwind_check_reliable(state); >> if (ret < 0) >> break; >> } >> + return ret; > > nit: > > I think you're looking more for comments on the approach and the > correctness of these patches, but from an initial read I'm still > putting it all together in my head. So this comment is on the coding > style. > > The above loop seems to check the current reliability state, then > unwind a frame then check the reliability, and then break based of > something which couldn't have been updated by the line immediately > above. I propose something like: > > unwind(...) { > ret = 0; > > while (!ret) { > if (need_reliable) { > unwind_check_reliable(state); > if (!state->reliable) > return -EINVAL; > } > if (!consume_entry(cookie, state->pc)) > return -EINVAL; > ret = unwind_next(state); > } > > return ret; > } > > This also removes the need for the call to unwind_check_reliable() > before the first unwind() below in arch_stack_walk_reliable(). > OK. Suggestion sounds reasonable. Will do. Madhavan > - Suraj > >> } >> NOKPROBE_SYMBOL(unwind); >> >> @@ -216,5 +337,37 @@ noinline notrace void >> arch_stack_walk(stack_trace_consume_fn consume_entry, >> unwind_init_from_task(&state, task); >> } >> >> - unwind(&state, consume_entry, cookie); >> + unwind(&state, false, consume_entry, cookie); >> +} >> + >> +noinline notrace int arch_stack_walk_reliable( >> + stack_trace_consume_fn consume_entry, >> + void *cookie, struct task_struct *task) >> +{ >> + struct stack_info stacks[] = { >> + stackinfo_get_task(task), >> + STACKINFO_CPU(irq), >> +#if defined(CONFIG_VMAP_STACK) >> + STACKINFO_CPU(overflow), >> +#endif >> +#if defined(CONFIG_VMAP_STACK) && defined(CONFIG_ARM_SDE_INTERFACE) >> + STACKINFO_SDEI(normal), >> + STACKINFO_SDEI(critical), >> +#endif >> + }; >> + struct unwind_state state = { >> + .stacks = stacks, >> + .nr_stacks = ARRAY_SIZE(stacks), >> + }; >> + int ret; >> + >> + if (task == current) >> + unwind_init_from_caller(&state); >> + else >> + unwind_init_from_task(&state, task); >> + unwind_check_reliable(&state); >> + >> + ret = unwind(&state, true, consume_entry, cookie); >> + >> + return ret == -ENOENT ? 0 : -EINVAL; >> } _______________________________________________ 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: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com> To: Suraj Jitindar Singh <sjitindarsingh@gmail.com> Cc: poimboe@redhat.com, peterz@infradead.org, chenzhongjin@huawei.com, mark.rutland@arm.com, broonie@kernel.org, nobuta.keiya@fujitsu.com, catalin.marinas@arm.com, will@kernel.org, jamorris@linux.microsoft.com, linux-arm-kernel@lists.infradead.org, live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH v3 19/22] arm64: unwinder: Add a reliability check in the unwinder based on ORC Date: Mon, 6 Mar 2023 10:52:09 -0600 [thread overview] Message-ID: <56308235-3893-75ac-a19f-497cc203c520@linux.microsoft.com> (raw) In-Reply-To: <88ab8c8348373e5c7c90c985dd92b5e06f32b16b.camel@gmail.com> On 2/22/23 22:07, Suraj Jitindar Singh wrote: > On Thu, 2023-02-02 at 01:40 -0600, madvenka@linux.microsoft.com wrote: >> From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com> >> >> Introduce a reliability flag in struct unwind_state. This will be set >> to >> false if the PC does not have a valid ORC or if the frame pointer >> computed >> from the ORC does not match the actual frame pointer. >> >> Now that the unwinder can validate the frame pointer, introduce >> arch_stack_walk_reliable(). >> >> Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com >>> >> --- >> arch/arm64/include/asm/stacktrace/common.h | 15 ++ >> arch/arm64/kernel/stacktrace.c | 167 >> ++++++++++++++++++++- >> 2 files changed, 175 insertions(+), 7 deletions(-) >> > > [snip] > >> -static void notrace unwind(struct unwind_state *state, >> +static int notrace unwind(struct unwind_state *state, bool >> need_reliable, >> stack_trace_consume_fn consume_entry, void >> *cookie) >> { >> - while (1) { >> - int ret; >> + int ret = 0; >> >> + while (1) { >> + if (need_reliable && !state->reliable) >> + return -EINVAL; >> if (!consume_entry(cookie, state->pc)) >> break; >> ret = unwind_next(state); >> + if (need_reliable && !ret) >> + unwind_check_reliable(state); >> if (ret < 0) >> break; >> } >> + return ret; > > nit: > > I think you're looking more for comments on the approach and the > correctness of these patches, but from an initial read I'm still > putting it all together in my head. So this comment is on the coding > style. > > The above loop seems to check the current reliability state, then > unwind a frame then check the reliability, and then break based of > something which couldn't have been updated by the line immediately > above. I propose something like: > > unwind(...) { > ret = 0; > > while (!ret) { > if (need_reliable) { > unwind_check_reliable(state); > if (!state->reliable) > return -EINVAL; > } > if (!consume_entry(cookie, state->pc)) > return -EINVAL; > ret = unwind_next(state); > } > > return ret; > } > > This also removes the need for the call to unwind_check_reliable() > before the first unwind() below in arch_stack_walk_reliable(). > OK. Suggestion sounds reasonable. Will do. Madhavan > - Suraj > >> } >> NOKPROBE_SYMBOL(unwind); >> >> @@ -216,5 +337,37 @@ noinline notrace void >> arch_stack_walk(stack_trace_consume_fn consume_entry, >> unwind_init_from_task(&state, task); >> } >> >> - unwind(&state, consume_entry, cookie); >> + unwind(&state, false, consume_entry, cookie); >> +} >> + >> +noinline notrace int arch_stack_walk_reliable( >> + stack_trace_consume_fn consume_entry, >> + void *cookie, struct task_struct *task) >> +{ >> + struct stack_info stacks[] = { >> + stackinfo_get_task(task), >> + STACKINFO_CPU(irq), >> +#if defined(CONFIG_VMAP_STACK) >> + STACKINFO_CPU(overflow), >> +#endif >> +#if defined(CONFIG_VMAP_STACK) && defined(CONFIG_ARM_SDE_INTERFACE) >> + STACKINFO_SDEI(normal), >> + STACKINFO_SDEI(critical), >> +#endif >> + }; >> + struct unwind_state state = { >> + .stacks = stacks, >> + .nr_stacks = ARRAY_SIZE(stacks), >> + }; >> + int ret; >> + >> + if (task == current) >> + unwind_init_from_caller(&state); >> + else >> + unwind_init_from_task(&state, task); >> + unwind_check_reliable(&state); >> + >> + ret = unwind(&state, true, consume_entry, cookie); >> + >> + return ret == -ENOENT ? 0 : -EINVAL; >> }
next prev parent reply other threads:[~2023-03-06 16:53 UTC|newest] Thread overview: 110+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <0337266cf19f4c98388e3f6d09f590d9de258dc7> 2023-02-02 7:40 ` [RFC PATCH v3 00/22] arm64: livepatch: Use ORC for dynamic frame pointer validation madvenka 2023-02-02 7:40 ` madvenka 2023-02-02 7:40 ` [RFC PATCH v3 01/22] objtool: Reorganize CFI code madvenka 2023-02-02 7:40 ` madvenka 2023-02-02 7:40 ` [RFC PATCH v3 02/22] objtool: Reorganize instruction-related code madvenka 2023-02-02 7:40 ` madvenka 2023-02-02 7:40 ` [RFC PATCH v3 03/22] objtool: Move decode_instructions() to a separate file madvenka 2023-02-02 7:40 ` madvenka 2023-02-02 7:40 ` [RFC PATCH v3 04/22] objtool: Reorganize Unwind hint code madvenka 2023-02-02 7:40 ` madvenka 2023-02-02 7:40 ` [RFC PATCH v3 05/22] objtool: Reorganize ORC types madvenka 2023-02-02 7:40 ` madvenka 2023-02-18 9:30 ` Suraj Jitindar Singh 2023-02-18 9:30 ` Suraj Jitindar Singh 2023-03-06 16:45 ` Madhavan T. Venkataraman 2023-03-06 16:45 ` Madhavan T. Venkataraman 2023-02-02 7:40 ` [RFC PATCH v3 06/22] objtool: Reorganize ORC code madvenka 2023-02-02 7:40 ` madvenka 2023-02-02 7:40 ` [RFC PATCH v3 07/22] objtool: Reorganize ORC kernel code madvenka 2023-02-02 7:40 ` madvenka 2023-02-02 7:40 ` [RFC PATCH v3 08/22] objtool: Introduce STATIC_CHECK madvenka 2023-02-02 7:40 ` madvenka 2023-02-02 7:40 ` [RFC PATCH v3 09/22] objtool: arm64: Add basic definitions and compile madvenka 2023-02-02 7:40 ` madvenka 2023-02-02 7:40 ` [RFC PATCH v3 10/22] objtool: arm64: Implement decoder for Dynamic FP validation madvenka 2023-02-02 7:40 ` madvenka 2023-02-02 7:40 ` [RFC PATCH v3 11/22] objtool: arm64: Invoke the decoder madvenka 2023-02-02 7:40 ` madvenka 2023-02-02 7:40 ` [RFC PATCH v3 12/22] objtool: arm64: Compute destinations for call and jump instructions madvenka 2023-02-02 7:40 ` madvenka 2023-02-02 7:40 ` [RFC PATCH v3 13/22] objtool: arm64: Walk instructions and compute CFI for each instruction madvenka 2023-02-02 7:40 ` madvenka 2023-02-02 7:40 ` [RFC PATCH v3 14/22] objtool: arm64: Generate ORC data from CFI for object files madvenka 2023-02-02 7:40 ` madvenka 2023-02-02 7:40 ` [RFC PATCH v3 15/22] objtool: arm64: Add unwind hint support madvenka 2023-02-02 7:40 ` madvenka 2023-02-02 7:40 ` [RFC PATCH v3 16/22] arm64: Add unwind hints to exception handlers madvenka 2023-02-02 7:40 ` madvenka 2023-02-02 7:40 ` [RFC PATCH v3 17/22] arm64: Add kernel and module support for ORC madvenka 2023-02-02 7:40 ` madvenka 2023-02-02 7:40 ` [RFC PATCH v3 18/22] arm64: Build the kernel with ORC information madvenka 2023-02-02 7:40 ` madvenka 2023-02-10 7:52 ` Tomohiro Misono (Fujitsu) 2023-02-10 7:52 ` Tomohiro Misono (Fujitsu) 2023-02-11 4:34 ` Madhavan T. Venkataraman 2023-02-11 4:34 ` Madhavan T. Venkataraman 2023-02-02 7:40 ` [RFC PATCH v3 19/22] arm64: unwinder: Add a reliability check in the unwinder based on ORC madvenka 2023-02-02 7:40 ` madvenka 2023-02-23 4:07 ` Suraj Jitindar Singh 2023-02-23 4:07 ` Suraj Jitindar Singh 2023-03-06 16:52 ` Madhavan T. Venkataraman [this message] 2023-03-06 16:52 ` Madhavan T. Venkataraman 2023-02-02 7:40 ` [RFC PATCH v3 20/22] arm64: Define HAVE_DYNAMIC_FTRACE_WITH_ARGS madvenka 2023-02-02 7:40 ` madvenka 2023-02-02 7:40 ` [RFC PATCH v3 21/22] arm64: Define TIF_PATCH_PENDING for livepatch madvenka 2023-02-02 7:40 ` madvenka 2023-02-02 7:40 ` [RFC PATCH v3 22/22] arm64: Enable livepatch for ARM64 madvenka 2023-02-02 7:40 ` madvenka 2023-03-01 3:12 ` [RFC PATCH v3 00/22] arm64: livepatch: Use ORC for dynamic frame pointer validation Tomohiro Misono (Fujitsu) 2023-03-01 3:12 ` Tomohiro Misono (Fujitsu) 2023-03-02 16:23 ` Petr Mladek 2023-03-02 16:23 ` Petr Mladek 2023-03-03 9:40 ` Tomohiro Misono (Fujitsu) 2023-03-03 9:40 ` Tomohiro Misono (Fujitsu) 2023-03-06 16:58 ` Madhavan T. Venkataraman 2023-03-06 16:58 ` Madhavan T. Venkataraman 2023-03-06 16:57 ` Madhavan T. Venkataraman 2023-03-06 16:57 ` Madhavan T. Venkataraman 2023-03-23 17:17 ` Mark Rutland 2023-03-23 17:17 ` Mark Rutland 2023-04-08 3:40 ` Madhavan T. Venkataraman 2023-04-08 3:40 ` Madhavan T. Venkataraman 2023-04-11 13:25 ` Mark Rutland 2023-04-11 13:25 ` Mark Rutland 2023-04-12 4:17 ` Josh Poimboeuf 2023-04-12 4:17 ` Josh Poimboeuf 2023-04-12 4:48 ` Madhavan T. Venkataraman 2023-04-12 4:48 ` Madhavan T. Venkataraman 2023-04-12 4:50 ` Madhavan T. Venkataraman 2023-04-12 4:50 ` Madhavan T. Venkataraman 2023-04-12 5:01 ` Josh Poimboeuf 2023-04-12 5:01 ` Josh Poimboeuf 2023-04-12 14:50 ` Madhavan T. Venkataraman 2023-04-12 14:50 ` Madhavan T. Venkataraman 2023-04-12 15:52 ` Josh Poimboeuf 2023-04-12 15:52 ` Josh Poimboeuf 2023-04-13 14:59 ` Madhavan T. Venkataraman 2023-04-13 14:59 ` Madhavan T. Venkataraman 2023-04-13 16:30 ` Josh Poimboeuf 2023-04-13 16:30 ` Josh Poimboeuf 2023-04-15 4:27 ` Madhavan T. Venkataraman 2023-04-15 4:27 ` Madhavan T. Venkataraman 2023-04-15 5:05 ` Josh Poimboeuf 2023-04-15 5:05 ` Josh Poimboeuf 2023-04-15 16:15 ` Madhavan T. Venkataraman 2023-04-15 16:15 ` Madhavan T. Venkataraman 2023-04-16 8:21 ` Indu Bhagat 2023-04-16 8:21 ` Indu Bhagat 2023-04-13 17:04 ` Nick Desaulniers 2023-04-13 17:04 ` Nick Desaulniers 2023-04-13 18:15 ` Jose E. Marchesi 2023-04-13 18:15 ` Jose E. Marchesi 2023-04-15 4:14 ` Madhavan T. Venkataraman 2023-04-15 4:14 ` Madhavan T. Venkataraman 2023-12-14 20:49 ` ARM64 Livepatch based on SFrame Madhavan T. Venkataraman 2023-12-14 20:49 ` Madhavan T. Venkataraman 2023-12-15 13:04 ` Mark Rutland 2023-12-15 13:04 ` Mark Rutland 2023-12-15 15:15 ` Madhavan T. Venkataraman 2023-12-15 15:15 ` Madhavan T. Venkataraman
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