From c0cfc337264c5e02e0bc79de6b62857999588879 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 25 Apr 2019 11:44:56 +0200 Subject: lib/stackdepot: Provide functions which operate on plain storage arrays The struct stack_trace indirection in the stack depot functions is a truly pointless excercise which requires horrible code at the callsites. Provide interfaces based on plain storage arrays. Signed-off-by: Thomas Gleixner Reviewed-by: Josh Poimboeuf Acked-by: Alexander Potapenko Cc: Andy Lutomirski Cc: Steven Rostedt Cc: Alexey Dobriyan Cc: Andrew Morton Cc: Christoph Lameter Cc: Pekka Enberg Cc: linux-mm@kvack.org Cc: David Rientjes Cc: Catalin Marinas Cc: Dmitry Vyukov Cc: Andrey Ryabinin Cc: kasan-dev@googlegroups.com Cc: Mike Rapoport Cc: Akinobu Mita Cc: Christoph Hellwig Cc: iommu@lists.linux-foundation.org Cc: Robin Murphy Cc: Marek Szyprowski Cc: Johannes Thumshirn Cc: David Sterba Cc: Chris Mason Cc: Josef Bacik Cc: linux-btrfs@vger.kernel.org Cc: dm-devel@redhat.com Cc: Mike Snitzer Cc: Alasdair Kergon Cc: Daniel Vetter Cc: intel-gfx@lists.freedesktop.org Cc: Joonas Lahtinen Cc: Maarten Lankhorst Cc: dri-devel@lists.freedesktop.org Cc: David Airlie Cc: Jani Nikula Cc: Rodrigo Vivi Cc: Tom Zanussi Cc: Miroslav Benes Cc: linux-arch@vger.kernel.org Link: https://lkml.kernel.org/r/20190425094801.414574828@linutronix.de --- lib/stackdepot.c | 70 +++++++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 51 insertions(+), 19 deletions(-) (limited to 'lib') diff --git a/lib/stackdepot.c b/lib/stackdepot.c index e513459a5601..e84f8e58495c 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -194,40 +194,60 @@ static inline struct stack_record *find_stack(struct stack_record *bucket, return NULL; } -void depot_fetch_stack(depot_stack_handle_t handle, struct stack_trace *trace) +/** + * stack_depot_fetch - Fetch stack entries from a depot + * + * @handle: Stack depot handle which was returned from + * stack_depot_save(). + * @entries: Pointer to store the entries address + * + * Return: The number of trace entries for this depot. + */ +unsigned int stack_depot_fetch(depot_stack_handle_t handle, + unsigned long **entries) { union handle_parts parts = { .handle = handle }; void *slab = stack_slabs[parts.slabindex]; size_t offset = parts.offset << STACK_ALLOC_ALIGN; struct stack_record *stack = slab + offset; - trace->nr_entries = trace->max_entries = stack->size; - trace->entries = stack->entries; - trace->skip = 0; + *entries = stack->entries; + return stack->size; +} +EXPORT_SYMBOL_GPL(stack_depot_fetch); + +void depot_fetch_stack(depot_stack_handle_t handle, struct stack_trace *trace) +{ + unsigned int nent = stack_depot_fetch(handle, &trace->entries); + + trace->max_entries = trace->nr_entries = nent; } EXPORT_SYMBOL_GPL(depot_fetch_stack); /** - * depot_save_stack - save stack in a stack depot. - * @trace - the stacktrace to save. - * @alloc_flags - flags for allocating additional memory if required. + * stack_depot_save - Save a stack trace from an array + * + * @entries: Pointer to storage array + * @nr_entries: Size of the storage array + * @alloc_flags: Allocation gfp flags * - * Returns the handle of the stack struct stored in depot. + * Return: The handle of the stack struct stored in depot */ -depot_stack_handle_t depot_save_stack(struct stack_trace *trace, - gfp_t alloc_flags) +depot_stack_handle_t stack_depot_save(unsigned long *entries, + unsigned int nr_entries, + gfp_t alloc_flags) { - u32 hash; - depot_stack_handle_t retval = 0; struct stack_record *found = NULL, **bucket; - unsigned long flags; + depot_stack_handle_t retval = 0; struct page *page = NULL; void *prealloc = NULL; + unsigned long flags; + u32 hash; - if (unlikely(trace->nr_entries == 0)) + if (unlikely(nr_entries == 0)) goto fast_exit; - hash = hash_stack(trace->entries, trace->nr_entries); + hash = hash_stack(entries, nr_entries); bucket = &stack_table[hash & STACK_HASH_MASK]; /* @@ -235,8 +255,8 @@ depot_stack_handle_t depot_save_stack(struct stack_trace *trace, * The smp_load_acquire() here pairs with smp_store_release() to * |bucket| below. */ - found = find_stack(smp_load_acquire(bucket), trace->entries, - trace->nr_entries, hash); + found = find_stack(smp_load_acquire(bucket), entries, + nr_entries, hash); if (found) goto exit; @@ -264,10 +284,10 @@ depot_stack_handle_t depot_save_stack(struct stack_trace *trace, spin_lock_irqsave(&depot_lock, flags); - found = find_stack(*bucket, trace->entries, trace->nr_entries, hash); + found = find_stack(*bucket, entries, nr_entries, hash); if (!found) { struct stack_record *new = - depot_alloc_stack(trace->entries, trace->nr_entries, + depot_alloc_stack(entries, nr_entries, hash, &prealloc, alloc_flags); if (new) { new->next = *bucket; @@ -297,4 +317,16 @@ exit: fast_exit: return retval; } +EXPORT_SYMBOL_GPL(stack_depot_save); + +/** + * depot_save_stack - save stack in a stack depot. + * @trace - the stacktrace to save. + * @alloc_flags - flags for allocating additional memory if required. + */ +depot_stack_handle_t depot_save_stack(struct stack_trace *trace, + gfp_t alloc_flags) +{ + return stack_depot_save(trace->entries, trace->nr_entries, alloc_flags); +} EXPORT_SYMBOL_GPL(depot_save_stack); -- cgit v1.2.3 From 30191250c2b3ef772cc6125e1c31ac84123f1d20 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 25 Apr 2019 11:45:04 +0200 Subject: fault-inject: Simplify stacktrace retrieval Replace the indirection through struct stack_trace with an invocation of the storage array based interface. Signed-off-by: Thomas Gleixner Reviewed-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Akinobu Mita Cc: Steven Rostedt Cc: Alexander Potapenko Cc: Alexey Dobriyan Cc: Andrew Morton Cc: Christoph Lameter Cc: Pekka Enberg Cc: linux-mm@kvack.org Cc: David Rientjes Cc: Catalin Marinas Cc: Dmitry Vyukov Cc: Andrey Ryabinin Cc: kasan-dev@googlegroups.com Cc: Mike Rapoport Cc: Christoph Hellwig Cc: iommu@lists.linux-foundation.org Cc: Robin Murphy Cc: Marek Szyprowski Cc: Johannes Thumshirn Cc: David Sterba Cc: Chris Mason Cc: Josef Bacik Cc: linux-btrfs@vger.kernel.org Cc: dm-devel@redhat.com Cc: Mike Snitzer Cc: Alasdair Kergon Cc: Daniel Vetter Cc: intel-gfx@lists.freedesktop.org Cc: Joonas Lahtinen Cc: Maarten Lankhorst Cc: dri-devel@lists.freedesktop.org Cc: David Airlie Cc: Jani Nikula Cc: Rodrigo Vivi Cc: Tom Zanussi Cc: Miroslav Benes Cc: linux-arch@vger.kernel.org Link: https://lkml.kernel.org/r/20190425094802.158306076@linutronix.de --- lib/fault-inject.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) (limited to 'lib') diff --git a/lib/fault-inject.c b/lib/fault-inject.c index cf7b129b0b2b..e26aa4f65eb9 100644 --- a/lib/fault-inject.c +++ b/lib/fault-inject.c @@ -65,22 +65,16 @@ static bool fail_task(struct fault_attr *attr, struct task_struct *task) static bool fail_stacktrace(struct fault_attr *attr) { - struct stack_trace trace; int depth = attr->stacktrace_depth; unsigned long entries[MAX_STACK_TRACE_DEPTH]; - int n; + int n, nr_entries; bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX); if (depth == 0) return found; - trace.nr_entries = 0; - trace.entries = entries; - trace.max_entries = depth; - trace.skip = 1; - - save_stack_trace(&trace); - for (n = 0; n < trace.nr_entries; n++) { + nr_entries = stack_trace_save(entries, depth, 1); + for (n = 0; n < nr_entries; n++) { if (attr->reject_start <= entries[n] && entries[n] < attr->reject_end) return false; -- cgit v1.2.3 From 56d8f079c51afc8b564b9fb0252d48e7b437c1e5 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 25 Apr 2019 11:45:20 +0200 Subject: lib/stackdepot: Remove obsolete functions No more users of the struct stack_trace based interfaces. Signed-off-by: Thomas Gleixner Reviewed-by: Josh Poimboeuf Acked-by: Alexander Potapenko Cc: Andy Lutomirski Cc: Steven Rostedt Cc: Alexey Dobriyan Cc: Andrew Morton Cc: Christoph Lameter Cc: Pekka Enberg Cc: linux-mm@kvack.org Cc: David Rientjes Cc: Catalin Marinas Cc: Dmitry Vyukov Cc: Andrey Ryabinin Cc: kasan-dev@googlegroups.com Cc: Mike Rapoport Cc: Akinobu Mita Cc: Christoph Hellwig Cc: iommu@lists.linux-foundation.org Cc: Robin Murphy Cc: Marek Szyprowski Cc: Johannes Thumshirn Cc: David Sterba Cc: Chris Mason Cc: Josef Bacik Cc: linux-btrfs@vger.kernel.org Cc: dm-devel@redhat.com Cc: Mike Snitzer Cc: Alasdair Kergon Cc: Daniel Vetter Cc: intel-gfx@lists.freedesktop.org Cc: Joonas Lahtinen Cc: Maarten Lankhorst Cc: dri-devel@lists.freedesktop.org Cc: David Airlie Cc: Jani Nikula Cc: Rodrigo Vivi Cc: Tom Zanussi Cc: Miroslav Benes Cc: linux-arch@vger.kernel.org Link: https://lkml.kernel.org/r/20190425094803.617937448@linutronix.de --- include/linux/stackdepot.h | 4 ---- lib/stackdepot.c | 20 -------------------- 2 files changed, 24 deletions(-) (limited to 'lib') diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h index 4297c6d2991d..0805dee1b6b8 100644 --- a/include/linux/stackdepot.h +++ b/include/linux/stackdepot.h @@ -23,13 +23,9 @@ typedef u32 depot_stack_handle_t; -struct stack_trace; - -depot_stack_handle_t depot_save_stack(struct stack_trace *trace, gfp_t flags); depot_stack_handle_t stack_depot_save(unsigned long *entries, unsigned int nr_entries, gfp_t gfp_flags); -void depot_fetch_stack(depot_stack_handle_t handle, struct stack_trace *trace); unsigned int stack_depot_fetch(depot_stack_handle_t handle, unsigned long **entries); diff --git a/lib/stackdepot.c b/lib/stackdepot.c index e84f8e58495c..605c61f65d94 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -216,14 +216,6 @@ unsigned int stack_depot_fetch(depot_stack_handle_t handle, } EXPORT_SYMBOL_GPL(stack_depot_fetch); -void depot_fetch_stack(depot_stack_handle_t handle, struct stack_trace *trace) -{ - unsigned int nent = stack_depot_fetch(handle, &trace->entries); - - trace->max_entries = trace->nr_entries = nent; -} -EXPORT_SYMBOL_GPL(depot_fetch_stack); - /** * stack_depot_save - Save a stack trace from an array * @@ -318,15 +310,3 @@ fast_exit: return retval; } EXPORT_SYMBOL_GPL(stack_depot_save); - -/** - * depot_save_stack - save stack in a stack depot. - * @trace - the stacktrace to save. - * @alloc_flags - flags for allocating additional memory if required. - */ -depot_stack_handle_t depot_save_stack(struct stack_trace *trace, - gfp_t alloc_flags) -{ - return stack_depot_save(trace->entries, trace->nr_entries, alloc_flags); -} -EXPORT_SYMBOL_GPL(depot_save_stack); -- cgit v1.2.3 From 214d8ca6ee854f696f75e75511fe66b409e656db Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 25 Apr 2019 11:45:21 +0200 Subject: stacktrace: Provide common infrastructure All architectures which support stacktrace carry duplicated code and do the stack storage and filtering at the architecture side. Provide a consolidated interface with a callback function for consuming the stack entries provided by the architecture specific stack walker. This removes lots of duplicated code and allows to implement better filtering than 'skip number of entries' in the future without touching any architecture specific code. Signed-off-by: Thomas Gleixner Reviewed-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: linux-arch@vger.kernel.org Cc: Steven Rostedt Cc: Alexander Potapenko Cc: Alexey Dobriyan Cc: Andrew Morton Cc: Christoph Lameter Cc: Pekka Enberg Cc: linux-mm@kvack.org Cc: David Rientjes Cc: Catalin Marinas Cc: Dmitry Vyukov Cc: Andrey Ryabinin Cc: kasan-dev@googlegroups.com Cc: Mike Rapoport Cc: Akinobu Mita Cc: Christoph Hellwig Cc: iommu@lists.linux-foundation.org Cc: Robin Murphy Cc: Marek Szyprowski Cc: Johannes Thumshirn Cc: David Sterba Cc: Chris Mason Cc: Josef Bacik Cc: linux-btrfs@vger.kernel.org Cc: dm-devel@redhat.com Cc: Mike Snitzer Cc: Alasdair Kergon Cc: Daniel Vetter Cc: intel-gfx@lists.freedesktop.org Cc: Joonas Lahtinen Cc: Maarten Lankhorst Cc: dri-devel@lists.freedesktop.org Cc: David Airlie Cc: Jani Nikula Cc: Rodrigo Vivi Cc: Tom Zanussi Cc: Miroslav Benes Link: https://lkml.kernel.org/r/20190425094803.713568606@linutronix.de --- include/linux/stacktrace.h | 39 ++++++++++ kernel/stacktrace.c | 173 +++++++++++++++++++++++++++++++++++++++++++++ lib/Kconfig | 4 ++ 3 files changed, 216 insertions(+) (limited to 'lib') diff --git a/include/linux/stacktrace.h b/include/linux/stacktrace.h index 40decfbb9a24..f0cfd12cb45e 100644 --- a/include/linux/stacktrace.h +++ b/include/linux/stacktrace.h @@ -23,6 +23,44 @@ unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store, unsigned int stack_trace_save_user(unsigned long *store, unsigned int size); /* Internal interfaces. Do not use in generic code */ +#ifdef CONFIG_ARCH_STACKWALK + +/** + * stack_trace_consume_fn - Callback for arch_stack_walk() + * @cookie: Caller supplied pointer handed back by arch_stack_walk() + * @addr: The stack entry address to consume + * @reliable: True when the stack entry is reliable. Required by + * some printk based consumers. + * + * Return: True, if the entry was consumed or skipped + * False, if there is no space left to store + */ +typedef bool (*stack_trace_consume_fn)(void *cookie, unsigned long addr, + bool reliable); +/** + * arch_stack_walk - Architecture specific function to walk the stack + * @consume_entry: Callback which is invoked by the architecture code for + * each entry. + * @cookie: Caller supplied pointer which is handed back to + * @consume_entry + * @task: Pointer to a task struct, can be NULL + * @regs: Pointer to registers, can be NULL + * + * ============ ======= ============================================ + * task regs + * ============ ======= ============================================ + * task NULL Stack trace from task (can be current) + * current regs Stack trace starting on regs->stackpointer + * ============ ======= ============================================ + */ +void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie, + struct task_struct *task, struct pt_regs *regs); +int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry, void *cookie, + struct task_struct *task); +void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie, + const struct pt_regs *regs); + +#else /* CONFIG_ARCH_STACKWALK */ struct stack_trace { unsigned int nr_entries, max_entries; unsigned long *entries; @@ -37,6 +75,7 @@ extern void save_stack_trace_tsk(struct task_struct *tsk, extern int save_stack_trace_tsk_reliable(struct task_struct *tsk, struct stack_trace *trace); extern void save_stack_trace_user(struct stack_trace *trace); +#endif /* !CONFIG_ARCH_STACKWALK */ #endif /* CONFIG_STACKTRACE */ #if defined(CONFIG_STACKTRACE) && defined(CONFIG_HAVE_RELIABLE_STACKTRACE) diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c index dd55312f3fe9..27bafc1e271e 100644 --- a/kernel/stacktrace.c +++ b/kernel/stacktrace.c @@ -5,6 +5,8 @@ * * Copyright (C) 2006 Red Hat, Inc., Ingo Molnar */ +#include +#include #include #include #include @@ -66,6 +68,175 @@ int stack_trace_snprint(char *buf, size_t size, unsigned long *entries, } EXPORT_SYMBOL_GPL(stack_trace_snprint); +#ifdef CONFIG_ARCH_STACKWALK + +struct stacktrace_cookie { + unsigned long *store; + unsigned int size; + unsigned int skip; + unsigned int len; +}; + +static bool stack_trace_consume_entry(void *cookie, unsigned long addr, + bool reliable) +{ + struct stacktrace_cookie *c = cookie; + + if (c->len >= c->size) + return false; + + if (c->skip > 0) { + c->skip--; + return true; + } + c->store[c->len++] = addr; + return c->len < c->size; +} + +static bool stack_trace_consume_entry_nosched(void *cookie, unsigned long addr, + bool reliable) +{ + if (in_sched_functions(addr)) + return true; + return stack_trace_consume_entry(cookie, addr, reliable); +} + +/** + * stack_trace_save - Save a stack trace into a storage array + * @store: Pointer to storage array + * @size: Size of the storage array + * @skipnr: Number of entries to skip at the start of the stack trace + * + * Return: Number of trace entries stored. + */ +unsigned int stack_trace_save(unsigned long *store, unsigned int size, + unsigned int skipnr) +{ + stack_trace_consume_fn consume_entry = stack_trace_consume_entry; + struct stacktrace_cookie c = { + .store = store, + .size = size, + .skip = skipnr + 1, + }; + + arch_stack_walk(consume_entry, &c, current, NULL); + return c.len; +} +EXPORT_SYMBOL_GPL(stack_trace_save); + +/** + * stack_trace_save_tsk - Save a task stack trace into a storage array + * @task: The task to examine + * @store: Pointer to storage array + * @size: Size of the storage array + * @skipnr: Number of entries to skip at the start of the stack trace + * + * Return: Number of trace entries stored. + */ +unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store, + unsigned int size, unsigned int skipnr) +{ + stack_trace_consume_fn consume_entry = stack_trace_consume_entry_nosched; + struct stacktrace_cookie c = { + .store = store, + .size = size, + .skip = skipnr + 1, + }; + + if (!try_get_task_stack(tsk)) + return 0; + + arch_stack_walk(consume_entry, &c, tsk, NULL); + put_task_stack(tsk); + return c.len; +} + +/** + * stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array + * @regs: Pointer to pt_regs to examine + * @store: Pointer to storage array + * @size: Size of the storage array + * @skipnr: Number of entries to skip at the start of the stack trace + * + * Return: Number of trace entries stored. + */ +unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store, + unsigned int size, unsigned int skipnr) +{ + stack_trace_consume_fn consume_entry = stack_trace_consume_entry; + struct stacktrace_cookie c = { + .store = store, + .size = size, + .skip = skipnr, + }; + + arch_stack_walk(consume_entry, &c, current, regs); + return c.len; +} + +#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE +/** + * stack_trace_save_tsk_reliable - Save task stack with verification + * @tsk: Pointer to the task to examine + * @store: Pointer to storage array + * @size: Size of the storage array + * + * Return: An error if it detects any unreliable features of the + * stack. Otherwise it guarantees that the stack trace is + * reliable and returns the number of entries stored. + * + * If the task is not 'current', the caller *must* ensure the task is inactive. + */ +int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store, + unsigned int size) +{ + stack_trace_consume_fn consume_entry = stack_trace_consume_entry; + struct stacktrace_cookie c = { + .store = store, + .size = size, + }; + int ret; + + /* + * If the task doesn't have a stack (e.g., a zombie), the stack is + * "reliably" empty. + */ + if (!try_get_task_stack(tsk)) + return 0; + + ret = arch_stack_walk_reliable(consume_entry, &c, tsk); + put_task_stack(tsk); + return ret; +} +#endif + +#ifdef CONFIG_USER_STACKTRACE_SUPPORT +/** + * stack_trace_save_user - Save a user space stack trace into a storage array + * @store: Pointer to storage array + * @size: Size of the storage array + * + * Return: Number of trace entries stored. + */ +unsigned int stack_trace_save_user(unsigned long *store, unsigned int size) +{ + stack_trace_consume_fn consume_entry = stack_trace_consume_entry; + struct stacktrace_cookie c = { + .store = store, + .size = size, + }; + + /* Trace user stack if not a kernel thread */ + if (!current->mm) + return 0; + + arch_stack_walk_user(consume_entry, &c, task_pt_regs(current)); + return c.len; +} +#endif + +#else /* CONFIG_ARCH_STACKWALK */ + /* * Architectures that do not implement save_stack_trace_*() * get these weak aliases and once-per-bootup warnings @@ -203,3 +374,5 @@ unsigned int stack_trace_save_user(unsigned long *store, unsigned int size) return trace.nr_entries; } #endif /* CONFIG_USER_STACKTRACE_SUPPORT */ + +#endif /* !CONFIG_ARCH_STACKWALK */ diff --git a/lib/Kconfig b/lib/Kconfig index a9e56539bd11..e86975bfca6a 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -597,6 +597,10 @@ config ARCH_HAS_UACCESS_FLUSHCACHE config ARCH_HAS_UACCESS_MCSAFE bool +# Temporary. Goes away when all archs are cleaned up +config ARCH_STACKWALK + bool + config STACKDEPOT bool select STACKTRACE -- cgit v1.2.3