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From: Arnd Bergmann <arnd@arndb.de>
To: unlisted-recipients:; (no To-header on input)
Cc: Arnd Bergmann <arnd@arndb.de>,
	"Uladzislau Rezki (Sony)" <urezki@gmail.com>,
	Roman Gushchin <guro@fb.com>, Michal Hocko <mhocko@suse.com>,
	Matthew Wilcox <willy@infradead.org>,
	Thomas Garnier <thgarnie@google.com>,
	Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Joel Fernandes <joelaf@google.com>,
	Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
	Tejun Heo <tj@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	Roman Penyaev <rpenyaev@suse.de>,
	Rick Edgecombe <rick.p.edgecombe@intel.com>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Mike Rapoport <rppt@linux.ibm.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [BUG]: mm/vmalloc: uninitialized variable access in pcpu_get_vm_areas
Date: Mon, 17 Jun 2019 14:14:11 +0200	[thread overview]
Message-ID: <20190617121427.77565-1-arnd@arndb.de> (raw)

gcc points out some obviously broken code in linux-next

mm/vmalloc.c: In function 'pcpu_get_vm_areas':
mm/vmalloc.c:991:4: error: 'lva' may be used uninitialized in this function [-Werror=maybe-uninitialized]
    insert_vmap_area_augment(lva, &va->rb_node,
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     &free_vmap_area_root, &free_vmap_area_list);
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mm/vmalloc.c:916:20: note: 'lva' was declared here
  struct vmap_area *lva;
                    ^~~

Remove the obviously broken code. This is almost certainly
not the correct solution, but it's what I have applied locally
to get a clean build again.

Please fix this properly.

Fixes: 68ad4a330433 ("mm/vmalloc.c: keep track of free blocks for vmap allocation")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 mm/vmalloc.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index a9213fc3802d..bfcf0124a773 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -984,14 +984,9 @@ adjust_va_to_fit_type(struct vmap_area *va,
 		return -1;
 	}
 
-	if (type != FL_FIT_TYPE) {
+	if (type == FL_FIT_TYPE)
 		augment_tree_propagate_from(va);
 
-		if (type == NE_FIT_TYPE)
-			insert_vmap_area_augment(lva, &va->rb_node,
-				&free_vmap_area_root, &free_vmap_area_list);
-	}
-
 	return 0;
 }
 
-- 
2.20.0


WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de>
Cc: Arnd Bergmann <arnd@arndb.de>,
	"Uladzislau Rezki (Sony)" <urezki@gmail.com>,
	Roman Gushchin <guro@fb.com>, Michal Hocko <mhocko@suse.com>,
	Matthew Wilcox <willy@infradead.org>,
	Thomas Garnier <thgarnie@google.com>,
	Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Joel Fernandes <joelaf@google.com>,
	Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
	Tejun Heo <tj@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	Roman Penyaev <rpenyaev@suse.de>,
	Rick Edgecombe <rick.p.edgecombe@intel.com>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Mike Rapoport <rppt@linux.ibm.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [BUG]: mm/vmalloc: uninitialized variable access in pcpu_get_vm_areas
Date: Mon, 17 Jun 2019 14:14:11 +0200	[thread overview]
Message-ID: <20190617121427.77565-1-arnd@arndb.de> (raw)

gcc points out some obviously broken code in linux-next

mm/vmalloc.c: In function 'pcpu_get_vm_areas':
mm/vmalloc.c:991:4: error: 'lva' may be used uninitialized in this function [-Werror=maybe-uninitialized]
    insert_vmap_area_augment(lva, &va->rb_node,
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     &free_vmap_area_root, &free_vmap_area_list);
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mm/vmalloc.c:916:20: note: 'lva' was declared here
  struct vmap_area *lva;
                    ^~~

Remove the obviously broken code. This is almost certainly
not the correct solution, but it's what I have applied locally
to get a clean build again.

Please fix this properly.

Fixes: 68ad4a330433 ("mm/vmalloc.c: keep track of free blocks for vmap allocation")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 mm/vmalloc.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index a9213fc3802d..bfcf0124a773 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -984,14 +984,9 @@ adjust_va_to_fit_type(struct vmap_area *va,
 		return -1;
 	}
 
-	if (type != FL_FIT_TYPE) {
+	if (type == FL_FIT_TYPE)
 		augment_tree_propagate_from(va);
 
-		if (type == NE_FIT_TYPE)
-			insert_vmap_area_augment(lva, &va->rb_node,
-				&free_vmap_area_root, &free_vmap_area_list);
-	}
-
 	return 0;
 }
 
-- 
2.20.0


             reply	other threads:[~2019-06-17 12:16 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-17 12:14 Arnd Bergmann [this message]
2019-06-17 12:14 ` [BUG]: mm/vmalloc: uninitialized variable access in pcpu_get_vm_areas Arnd Bergmann
2019-06-17 13:49 ` Roman Penyaev
2019-06-17 14:04   ` Arnd Bergmann
2019-06-17 14:04     ` Arnd Bergmann
2019-06-17 14:40     ` Roman Penyaev
2019-06-17 14:12 ` Uladzislau Rezki
2019-06-17 14:44   ` Arnd Bergmann
2019-06-17 14:44     ` Arnd Bergmann
2019-06-17 14:50     ` Roman Penyaev
2019-06-17 14:50     ` Arnd Bergmann
2019-06-17 14:50       ` Arnd Bergmann
2019-06-17 16:57       ` Uladzislau Rezki
2019-06-17 19:29         ` Arnd Bergmann
2019-06-17 19:29           ` Arnd Bergmann
2019-06-18  8:01           ` Arnd Bergmann
2019-06-18  8:01             ` Arnd Bergmann
2019-06-18  8:53             ` Uladzislau Rezki

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