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From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
	x86@kernel.org, Andy Lutomirski <luto@kernel.org>,
	linux-mm@kvack.org, Mike Rapoport <rppt@linux.vnet.ibm.com>,
	David Rientjes <rientjes@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Alexander Potapenko <glider@google.com>,
	Alexey Dobriyan <adobriyan@gmail.com>,
	Christoph Lameter <cl@linux.com>,
	Pekka Enberg <penberg@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	kasan-dev@googlegroups.com, Akinobu Mita <akinobu.mita@gmail.com>,
	Christoph Hellwig <hch@lst.de>,
	iommu@lists.linux-foundation.org,
	Robin Murphy <robin.murphy@arm.com>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Johannes Thumshirn <jthumshirn@suse.de>,
	David Sterba <dsterba@suse.com>, Chris Mason <clm@fb.com>,
	Josef Bacik <josef@toxicpanda.com>,
	linux-btrfs@vger.kernel.org, dm-devel@redhat.com,
	Mike Snitzer <snitzer@redhat.com>,
	Alasdair Kergon <agk@redhat.com>, Daniel Vetter <daniel@ffwll.ch>,
	intel-gfx@lists.freedesktop.org,
	Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	dri-devel@lists.freedesktop.org, David Airlie <airlied@linux.ie>,
	Jani Nikula <jani.nikula@linux.intel.com>,
	Rodrigo Vivi <rodrigo.vivi@intel.com>,
	Tom Zanussi <tom.zanussi@linux.intel.com>,
	Miroslav Benes <mbenes@suse.cz>,
	linux-arch@vger.kernel.org
Subject: [patch V3 10/29] mm/page_owner: Simplify stack trace handling
Date: Thu, 25 Apr 2019 11:45:03 +0200
Message-ID: <20190425094802.067210525@linutronix.de> (raw)
In-Reply-To: <20190425094453.875139013@linutronix.de>

Replace the indirection through struct stack_trace by using the storage
array based interfaces.

The original code in all printing functions is really wrong. It allocates a
storage array on stack which is unused because depot_fetch_stack() does not
store anything in it. It overwrites the entries pointer in the stack_trace
struct so it points to the depot storage.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
 mm/page_owner.c |   79 +++++++++++++++++++-------------------------------------
 1 file changed, 28 insertions(+), 51 deletions(-)

--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -58,15 +58,10 @@ static bool need_page_owner(void)
 static __always_inline depot_stack_handle_t create_dummy_stack(void)
 {
 	unsigned long entries[4];
-	struct stack_trace dummy;
+	unsigned int nr_entries;
 
-	dummy.nr_entries = 0;
-	dummy.max_entries = ARRAY_SIZE(entries);
-	dummy.entries = &entries[0];
-	dummy.skip = 0;
-
-	save_stack_trace(&dummy);
-	return depot_save_stack(&dummy, GFP_KERNEL);
+	nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
+	return stack_depot_save(entries, nr_entries, GFP_KERNEL);
 }
 
 static noinline void register_dummy_stack(void)
@@ -120,46 +115,39 @@ void __reset_page_owner(struct page *pag
 	}
 }
 
-static inline bool check_recursive_alloc(struct stack_trace *trace,
-					unsigned long ip)
+static inline bool check_recursive_alloc(unsigned long *entries,
+					 unsigned int nr_entries,
+					 unsigned long ip)
 {
-	int i;
+	unsigned int i;
 
-	if (!trace->nr_entries)
-		return false;
-
-	for (i = 0; i < trace->nr_entries; i++) {
-		if (trace->entries[i] == ip)
+	for (i = 0; i < nr_entries; i++) {
+		if (entries[i] == ip)
 			return true;
 	}
-
 	return false;
 }
 
 static noinline depot_stack_handle_t save_stack(gfp_t flags)
 {
 	unsigned long entries[PAGE_OWNER_STACK_DEPTH];
-	struct stack_trace trace = {
-		.nr_entries = 0,
-		.entries = entries,
-		.max_entries = PAGE_OWNER_STACK_DEPTH,
-		.skip = 2
-	};
 	depot_stack_handle_t handle;
+	unsigned int nr_entries;
 
-	save_stack_trace(&trace);
+	nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 2);
 
 	/*
-	 * We need to check recursion here because our request to stackdepot
-	 * could trigger memory allocation to save new entry. New memory
-	 * allocation would reach here and call depot_save_stack() again
-	 * if we don't catch it. There is still not enough memory in stackdepot
-	 * so it would try to allocate memory again and loop forever.
+	 * We need to check recursion here because our request to
+	 * stackdepot could trigger memory allocation to save new
+	 * entry. New memory allocation would reach here and call
+	 * stack_depot_save_entries() again if we don't catch it. There is
+	 * still not enough memory in stackdepot so it would try to
+	 * allocate memory again and loop forever.
 	 */
-	if (check_recursive_alloc(&trace, _RET_IP_))
+	if (check_recursive_alloc(entries, nr_entries, _RET_IP_))
 		return dummy_handle;
 
-	handle = depot_save_stack(&trace, flags);
+	handle = stack_depot_save(entries, nr_entries, flags);
 	if (!handle)
 		handle = failure_handle;
 
@@ -337,16 +325,10 @@ print_page_owner(char __user *buf, size_
 		struct page *page, struct page_owner *page_owner,
 		depot_stack_handle_t handle)
 {
-	int ret;
-	int pageblock_mt, page_mt;
+	int ret, pageblock_mt, page_mt;
+	unsigned long *entries;
+	unsigned int nr_entries;
 	char *kbuf;
-	unsigned long entries[PAGE_OWNER_STACK_DEPTH];
-	struct stack_trace trace = {
-		.nr_entries = 0,
-		.entries = entries,
-		.max_entries = PAGE_OWNER_STACK_DEPTH,
-		.skip = 0
-	};
 
 	count = min_t(size_t, count, PAGE_SIZE);
 	kbuf = kmalloc(count, GFP_KERNEL);
@@ -375,8 +357,8 @@ print_page_owner(char __user *buf, size_
 	if (ret >= count)
 		goto err;
 
-	depot_fetch_stack(handle, &trace);
-	ret += snprint_stack_trace(kbuf + ret, count - ret, &trace, 0);
+	nr_entries = stack_depot_fetch(handle, &entries);
+	ret += stack_trace_snprint(kbuf + ret, count - ret, entries, nr_entries, 0);
 	if (ret >= count)
 		goto err;
 
@@ -407,14 +389,9 @@ void __dump_page_owner(struct page *page
 {
 	struct page_ext *page_ext = lookup_page_ext(page);
 	struct page_owner *page_owner;
-	unsigned long entries[PAGE_OWNER_STACK_DEPTH];
-	struct stack_trace trace = {
-		.nr_entries = 0,
-		.entries = entries,
-		.max_entries = PAGE_OWNER_STACK_DEPTH,
-		.skip = 0
-	};
 	depot_stack_handle_t handle;
+	unsigned long *entries;
+	unsigned int nr_entries;
 	gfp_t gfp_mask;
 	int mt;
 
@@ -438,10 +415,10 @@ void __dump_page_owner(struct page *page
 		return;
 	}
 
-	depot_fetch_stack(handle, &trace);
+	nr_entries = stack_depot_fetch(handle, &entries);
 	pr_alert("page allocated via order %u, migratetype %s, gfp_mask %#x(%pGg)\n",
 		 page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask);
-	print_stack_trace(&trace, 0);
+	stack_trace_print(entries, nr_entries, 0);
 
 	if (page_owner->last_migrate_reason != -1)
 		pr_alert("page has been migrated, last migrate reason: %s\n",



  parent reply index

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-25  9:44 [patch V3 00/29] stacktrace: Consolidate stack trace usage Thomas Gleixner
2019-04-25  9:44 ` [patch V3 01/29] tracing: Cleanup stack trace code Thomas Gleixner
2019-04-25  9:44 ` [patch V3 02/29] stacktrace: Provide helpers for common stack trace operations Thomas Gleixner
2019-04-25  9:44 ` [patch V3 03/29] lib/stackdepot: Provide functions which operate on plain storage arrays Thomas Gleixner
2019-04-25  9:44 ` [patch V3 04/29] backtrace-test: Simplify stack trace handling Thomas Gleixner
2019-04-25  9:44 ` [patch V3 05/29] proc: Simplify task stack retrieval Thomas Gleixner
2019-04-25  9:44 ` [patch V3 06/29] latency_top: Simplify stack trace handling Thomas Gleixner
2019-04-25  9:45 ` [patch V3 07/29] mm/slub: Simplify stack trace retrieval Thomas Gleixner
2019-04-25  9:45 ` [patch V3 08/29] mm/kmemleak: Simplify stacktrace handling Thomas Gleixner
2019-04-25  9:45 ` [patch V3 09/29] mm/kasan: " Thomas Gleixner
2019-04-25  9:45 ` Thomas Gleixner [this message]
2019-04-25  9:45 ` [patch V3 11/29] fault-inject: Simplify stacktrace retrieval Thomas Gleixner
2019-04-25  9:45 ` [patch V3 12/29] dma/debug: Simplify stracktrace retrieval Thomas Gleixner
2019-04-25  9:45 ` [patch V3 13/29] btrfs: ref-verify: Simplify stack trace retrieval Thomas Gleixner
2019-04-25  9:45 ` [patch V3 14/29] dm bufio: " Thomas Gleixner
2019-04-25  9:45 ` [patch V3 15/29] dm persistent data: Simplify stack trace handling Thomas Gleixner
2019-04-25  9:45 ` [patch V3 16/29] drm: Simplify stacktrace handling Thomas Gleixner
2019-04-25  9:45 ` [patch V3 17/29] lockdep: Remove unused trace argument from print_circular_bug() Thomas Gleixner
2019-04-25  9:45 ` [patch V3 18/29] lockdep: Remove save argument from check_prev_add() Thomas Gleixner
2019-04-25 13:35   ` Peter Zijlstra
2019-04-25  9:45 ` [patch V3 19/29] lockdep: Simplify stack trace handling Thomas Gleixner
2019-04-25  9:45 ` [patch V3 20/29] tracing: Simplify stacktrace retrieval in histograms Thomas Gleixner
2019-04-25  9:45 ` [patch V3 21/29] tracing: Use percpu stack trace buffer more intelligently Thomas Gleixner
2019-04-25 13:29   ` Josh Poimboeuf
2019-04-25  9:45 ` [patch V3 22/29] tracing: Make ftrace_trace_userstack() static and conditional Thomas Gleixner
2019-04-25  9:45 ` [patch V3 23/29] tracing: Simplify stack trace retrieval Thomas Gleixner
2019-04-25  9:45 ` [patch V3 24/29] tracing: Remove the last struct stack_trace usage Thomas Gleixner
2019-04-25 13:30   ` Josh Poimboeuf
2019-04-25  9:45 ` [patch V3 25/29] livepatch: Simplify stack trace retrieval Thomas Gleixner
2019-04-25  9:45 ` [patch V3 26/29] stacktrace: Remove obsolete functions Thomas Gleixner
2019-04-25  9:45 ` [patch V3 27/29] lib/stackdepot: " Thomas Gleixner
2019-04-25  9:45 ` [patch V3 28/29] stacktrace: Provide common infrastructure Thomas Gleixner
2019-04-25  9:45 ` [patch V3 29/29] x86/stacktrace: Use " Thomas Gleixner
2019-04-25 10:09 ` [patch V3 00/29] stacktrace: Consolidate stack trace usage Ingo Molnar
2019-04-25 13:31 ` Josh Poimboeuf

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