FAILED: patch "[PATCH] ftrace: Fix possible warning on checking all pages used in" failed to apply to 5.10-stable tree

FAILED: patch "[PATCH] ftrace: Fix possible warning on checking all pages used in" failed to apply to 5.10-stable tree

[gregkh]

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 26efd79c4624294e553aeaa3439c646729bad084
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2023072114-giblet-unzip-f1db@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

26efd79c4624 ("ftrace: Fix possible warning on checking all pages used in ftrace_process_locs()")
db42523b4f3e ("ftrace: Store the order of pages allocated in ftrace_page")
59300b36f85f ("ftrace: Check if pages were allocated before calling free_pages()")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 26efd79c4624294e553aeaa3439c646729bad084 Mon Sep 17 00:00:00 2001
From: Zheng Yejian <zhengyejian1@huawei.com>
Date: Wed, 12 Jul 2023 14:04:52 +0800
Subject: [PATCH] ftrace: Fix possible warning on checking all pages used in
 ftrace_process_locs()

As comments in ftrace_process_locs(), there may be NULL pointers in
mcount_loc section:
 > Some architecture linkers will pad between
 > the different mcount_loc sections of different
 > object files to satisfy alignments.
 > Skip any NULL pointers.

After commit 20e5227e9f55 ("ftrace: allow NULL pointers in mcount_loc"),
NULL pointers will be accounted when allocating ftrace pages but skipped
before adding into ftrace pages, this may result in some pages not being
used. Then after commit 706c81f87f84 ("ftrace: Remove extra helper
functions"), warning may occur at:
  WARN_ON(pg->next);

To fix it, only warn for case that no pointers skipped but pages not used
up, then free those unused pages after releasing ftrace_lock.

Link: https://lore.kernel.org/linux-trace-kernel/20230712060452.3175675-1-zhengyejian1@huawei.com

Cc: stable@vger.kernel.org
Fixes: 706c81f87f84 ("ftrace: Remove extra helper functions")
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 3740aca79fe7..05c0024815bf 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3305,6 +3305,22 @@ static int ftrace_allocate_records(struct ftrace_page *pg, int count)
 	return cnt;
 }
 
+static void ftrace_free_pages(struct ftrace_page *pages)
+{
+	struct ftrace_page *pg = pages;
+
+	while (pg) {
+		if (pg->records) {
+			free_pages((unsigned long)pg->records, pg->order);
+			ftrace_number_of_pages -= 1 << pg->order;
+		}
+		pages = pg->next;
+		kfree(pg);
+		pg = pages;
+		ftrace_number_of_groups--;
+	}
+}
+
 static struct ftrace_page *
 ftrace_allocate_pages(unsigned long num_to_init)
 {
@@ -3343,17 +3359,7 @@ ftrace_allocate_pages(unsigned long num_to_init)
 	return start_pg;
 
  free_pages:
-	pg = start_pg;
-	while (pg) {
-		if (pg->records) {
-			free_pages((unsigned long)pg->records, pg->order);
-			ftrace_number_of_pages -= 1 << pg->order;
-		}
-		start_pg = pg->next;
-		kfree(pg);
-		pg = start_pg;
-		ftrace_number_of_groups--;
-	}
+	ftrace_free_pages(start_pg);
 	pr_info("ftrace: FAILED to allocate memory for functions\n");
 	return NULL;
 }
@@ -6471,9 +6477,11 @@ static int ftrace_process_locs(struct module *mod,
 			       unsigned long *start,
 			       unsigned long *end)
 {
+	struct ftrace_page *pg_unuse = NULL;
 	struct ftrace_page *start_pg;
 	struct ftrace_page *pg;
 	struct dyn_ftrace *rec;
+	unsigned long skipped = 0;
 	unsigned long count;
 	unsigned long *p;
 	unsigned long addr;
@@ -6536,8 +6544,10 @@ static int ftrace_process_locs(struct module *mod,
 		 * object files to satisfy alignments.
 		 * Skip any NULL pointers.
 		 */
-		if (!addr)
+		if (!addr) {
+			skipped++;
 			continue;
+		}
 
 		end_offset = (pg->index+1) * sizeof(pg->records[0]);
 		if (end_offset > PAGE_SIZE << pg->order) {
@@ -6551,8 +6561,10 @@ static int ftrace_process_locs(struct module *mod,
 		rec->ip = addr;
 	}
 
-	/* We should have used all pages */
-	WARN_ON(pg->next);
+	if (pg->next) {
+		pg_unuse = pg->next;
+		pg->next = NULL;
+	}
 
 	/* Assign the last page to ftrace_pages */
 	ftrace_pages = pg;
@@ -6574,6 +6586,11 @@ static int ftrace_process_locs(struct module *mod,
  out:
 	mutex_unlock(&ftrace_lock);
 
+	/* We should have used all pages unless we skipped some */
+	if (pg_unuse) {
+		WARN_ON(!skipped);
+		ftrace_free_pages(pg_unuse);
+	}
 	return ret;
 }
 

[PATCH 5.10 0/2] re: FAILED: patch "[PATCH] ftrace: Fix possible

[Zheng Yejian]

Resolve backport failed due to lack of dependency commit
db42523b4f3e ("ftrace: Store the order of pages allocated in ftrace_page")

Linus Torvalds (1):
  ftrace: Store the order of pages allocated in ftrace_page

Zheng Yejian (1):
  ftrace: Fix possible warning on checking all pages used in
    ftrace_process_locs()

 kernel/trace/ftrace.c | 72 ++++++++++++++++++++++++++-----------------
 1 file changed, 44 insertions(+), 28 deletions(-)

-- 
2.25.1

[PATCH 5.10 1/2] ftrace: Store the order of pages allocated in ftrace_page

[Zheng Yejian]

From: Linus Torvalds <torvalds@linux-foundation.org>

commit db42523b4f3e83ff86b53cdda219a9767c8b047f upstream.

Instead of saving the size of the records field of the ftrace_page, store
the order it uses to allocate the pages, as that is what is needed to know
in order to free the pages. This simplifies the code.

Link: https://lore.kernel.org/lkml/CAHk-=whyMxheOqXAORt9a7JK9gc9eHTgCJ55Pgs4p=X3RrQubQ@mail.gmail.com/

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[ change log written by Steven Rostedt ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
---
 kernel/trace/ftrace.c | 35 +++++++++++++++++------------------
 1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 3dab978c156d..acba76c0c5c3 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1091,7 +1091,7 @@ struct ftrace_page {
 	struct ftrace_page	*next;
 	struct dyn_ftrace	*records;
 	int			index;
-	int			size;
+	int			order;
 };
 
 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
@@ -3188,7 +3188,7 @@ static int ftrace_allocate_records(struct ftrace_page *pg, int count)
 	ftrace_number_of_groups++;
 
 	cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
-	pg->size = cnt;
+	pg->order = order;
 
 	if (cnt > count)
 		cnt = count;
@@ -3201,7 +3201,6 @@ ftrace_allocate_pages(unsigned long num_to_init)
 {
 	struct ftrace_page *start_pg;
 	struct ftrace_page *pg;
-	int order;
 	int cnt;
 
 	if (!num_to_init)
@@ -3237,13 +3236,13 @@ ftrace_allocate_pages(unsigned long num_to_init)
  free_pages:
 	pg = start_pg;
 	while (pg) {
-		order = get_count_order(pg->size / ENTRIES_PER_PAGE);
-		if (order >= 0)
-			free_pages((unsigned long)pg->records, order);
+		if (pg->records) {
+			free_pages((unsigned long)pg->records, pg->order);
+			ftrace_number_of_pages -= 1 << pg->order;
+		}
 		start_pg = pg->next;
 		kfree(pg);
 		pg = start_pg;
-		ftrace_number_of_pages -= 1 << order;
 		ftrace_number_of_groups--;
 	}
 	pr_info("ftrace: FAILED to allocate memory for functions\n");
@@ -6239,6 +6238,7 @@ static int ftrace_process_locs(struct module *mod,
 	p = start;
 	pg = start_pg;
 	while (p < end) {
+		unsigned long end_offset;
 		addr = ftrace_call_adjust(*p++);
 		/*
 		 * Some architecture linkers will pad between
@@ -6249,7 +6249,8 @@ static int ftrace_process_locs(struct module *mod,
 		if (!addr)
 			continue;
 
-		if (pg->index == pg->size) {
+		end_offset = (pg->index+1) * sizeof(pg->records[0]);
+		if (end_offset > PAGE_SIZE << pg->order) {
 			/* We should have allocated enough */
 			if (WARN_ON(!pg->next))
 				break;
@@ -6418,7 +6419,6 @@ void ftrace_release_mod(struct module *mod)
 	struct ftrace_page **last_pg;
 	struct ftrace_page *tmp_page = NULL;
 	struct ftrace_page *pg;
-	int order;
 
 	mutex_lock(&ftrace_lock);
 
@@ -6469,12 +6469,12 @@ void ftrace_release_mod(struct module *mod)
 		/* Needs to be called outside of ftrace_lock */
 		clear_mod_from_hashes(pg);
 
-		order = get_count_order(pg->size / ENTRIES_PER_PAGE);
-		if (order >= 0)
-			free_pages((unsigned long)pg->records, order);
+		if (pg->records) {
+			free_pages((unsigned long)pg->records, pg->order);
+			ftrace_number_of_pages -= 1 << pg->order;
+		}
 		tmp_page = pg->next;
 		kfree(pg);
-		ftrace_number_of_pages -= 1 << order;
 		ftrace_number_of_groups--;
 	}
 }
@@ -6792,7 +6792,6 @@ void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
 	struct ftrace_mod_map *mod_map = NULL;
 	struct ftrace_init_func *func, *func_next;
 	struct list_head clear_hash;
-	int order;
 
 	INIT_LIST_HEAD(&clear_hash);
 
@@ -6830,10 +6829,10 @@ void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
 		ftrace_update_tot_cnt--;
 		if (!pg->index) {
 			*last_pg = pg->next;
-			order = get_count_order(pg->size / ENTRIES_PER_PAGE);
-			if (order >= 0)
-				free_pages((unsigned long)pg->records, order);
-			ftrace_number_of_pages -= 1 << order;
+			if (pg->records) {
+				free_pages((unsigned long)pg->records, pg->order);
+				ftrace_number_of_pages -= 1 << pg->order;
+			}
 			ftrace_number_of_groups--;
 			kfree(pg);
 			pg = container_of(last_pg, struct ftrace_page, next);
-- 
2.25.1

[PATCH 5.10 2/2] ftrace: Fix possible warning on checking all pages used in ftrace_process_locs()

[Zheng Yejian]

commit 26efd79c4624294e553aeaa3439c646729bad084 upstream.

As comments in ftrace_process_locs(), there may be NULL pointers in
mcount_loc section:
 > Some architecture linkers will pad between
 > the different mcount_loc sections of different
 > object files to satisfy alignments.
 > Skip any NULL pointers.

After commit 20e5227e9f55 ("ftrace: allow NULL pointers in mcount_loc"),
NULL pointers will be accounted when allocating ftrace pages but skipped
before adding into ftrace pages, this may result in some pages not being
used. Then after commit 706c81f87f84 ("ftrace: Remove extra helper
functions"), warning may occur at:
  WARN_ON(pg->next);

To fix it, only warn for case that no pointers skipped but pages not used
up, then free those unused pages after releasing ftrace_lock.

Link: https://lore.kernel.org/linux-trace-kernel/20230712060452.3175675-1-zhengyejian1@huawei.com

Cc: stable@vger.kernel.org
Fixes: 706c81f87f84 ("ftrace: Remove extra helper functions")
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c | 45 +++++++++++++++++++++++++++++--------------
 1 file changed, 31 insertions(+), 14 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index acba76c0c5c3..31fec924b7c4 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3196,6 +3196,22 @@ static int ftrace_allocate_records(struct ftrace_page *pg, int count)
 	return cnt;
 }
 
+static void ftrace_free_pages(struct ftrace_page *pages)
+{
+	struct ftrace_page *pg = pages;
+
+	while (pg) {
+		if (pg->records) {
+			free_pages((unsigned long)pg->records, pg->order);
+			ftrace_number_of_pages -= 1 << pg->order;
+		}
+		pages = pg->next;
+		kfree(pg);
+		pg = pages;
+		ftrace_number_of_groups--;
+	}
+}
+
 static struct ftrace_page *
 ftrace_allocate_pages(unsigned long num_to_init)
 {
@@ -3234,17 +3250,7 @@ ftrace_allocate_pages(unsigned long num_to_init)
 	return start_pg;
 
  free_pages:
-	pg = start_pg;
-	while (pg) {
-		if (pg->records) {
-			free_pages((unsigned long)pg->records, pg->order);
-			ftrace_number_of_pages -= 1 << pg->order;
-		}
-		start_pg = pg->next;
-		kfree(pg);
-		pg = start_pg;
-		ftrace_number_of_groups--;
-	}
+	ftrace_free_pages(start_pg);
 	pr_info("ftrace: FAILED to allocate memory for functions\n");
 	return NULL;
 }
@@ -6190,9 +6196,11 @@ static int ftrace_process_locs(struct module *mod,
 			       unsigned long *start,
 			       unsigned long *end)
 {
+	struct ftrace_page *pg_unuse = NULL;
 	struct ftrace_page *start_pg;
 	struct ftrace_page *pg;
 	struct dyn_ftrace *rec;
+	unsigned long skipped = 0;
 	unsigned long count;
 	unsigned long *p;
 	unsigned long addr;
@@ -6246,8 +6254,10 @@ static int ftrace_process_locs(struct module *mod,
 		 * object files to satisfy alignments.
 		 * Skip any NULL pointers.
 		 */
-		if (!addr)
+		if (!addr) {
+			skipped++;
 			continue;
+		}
 
 		end_offset = (pg->index+1) * sizeof(pg->records[0]);
 		if (end_offset > PAGE_SIZE << pg->order) {
@@ -6261,8 +6271,10 @@ static int ftrace_process_locs(struct module *mod,
 		rec->ip = addr;
 	}
 
-	/* We should have used all pages */
-	WARN_ON(pg->next);
+	if (pg->next) {
+		pg_unuse = pg->next;
+		pg->next = NULL;
+	}
 
 	/* Assign the last page to ftrace_pages */
 	ftrace_pages = pg;
@@ -6284,6 +6296,11 @@ static int ftrace_process_locs(struct module *mod,
  out:
 	mutex_unlock(&ftrace_lock);
 
+	/* We should have used all pages unless we skipped some */
+	if (pg_unuse) {
+		WARN_ON(!skipped);
+		ftrace_free_pages(pg_unuse);
+	}
 	return ret;
 }
 
-- 
2.25.1

Re: [PATCH 5.10 0/2] re: FAILED: patch "[PATCH] ftrace: Fix possible

[Greg KH]

On Mon, Jul 24, 2023 at 10:29:22AM +0800, Zheng Yejian wrote:
> Resolve backport failed due to lack of dependency commit
> db42523b4f3e ("ftrace: Store the order of pages allocated in ftrace_page")
> 
> Linus Torvalds (1):
>   ftrace: Store the order of pages allocated in ftrace_page
> 
> Zheng Yejian (1):
>   ftrace: Fix possible warning on checking all pages used in
>     ftrace_process_locs()
> 
>  kernel/trace/ftrace.c | 72 ++++++++++++++++++++++++++-----------------
>  1 file changed, 44 insertions(+), 28 deletions(-)
> 
> -- 
> 2.25.1
> 

Both now queued up, thanks.

greg k-h