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authorJohannes Weiner <hannes@cmpxchg.org>2009-08-06 15:07:36 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-08-07 10:39:56 -0700
commit0035fe00f77d2b0a1a2d001f7442136d1ec5aefa (patch)
tree1e203e7674623d64c7e1cc260af200e7ad45e08a
parent521594442cc62d1c2af8436a05ab5918b7730b19 (diff)
downloadop-kernel-dev-0035fe00f77d2b0a1a2d001f7442136d1ec5aefa.zip
op-kernel-dev-0035fe00f77d2b0a1a2d001f7442136d1ec5aefa.tar.gz
fbcon: don't use vc_resize() on initialization
Catalin and kmemleak spotted a leak of a VC screen buffer in vc_allocate() due to the following chain of events: vc_allocate() visual_init(init=1) vc->vc_sw->con_init(init=1) fbcon_init() vc_resize() vc->screen_buf = kmalloc() vc->screen_buf = kmalloc() The common way for the VC drivers is to set the screen dimension parameters manually in the init case and only call vc_resize() for !init - which allocates a screen buffer according to the new dimensions. fbcon instead would do vc_resize() unconditionally and afterwards set the dimensions manually (again) for !init - i.e. completely upside down. The vc_resize() allocated buffer would then get lost by vc_allocate() allocating a fresh one. Use vc_resize() only for actual resizing to close the leak. Set the dimensions manually only in initialization mode to remove the redundant setting in resize mode. The kmemleak trace from Catalin: unreferenced object 0xde158000 (size 12288): comm "Xorg", pid 1439, jiffies 4294961016 hex dump (first 32 bytes): 20 00 20 00 20 00 20 00 20 00 20 00 20 00 20 00 . . . . . . . . 20 00 20 00 20 00 20 00 20 00 20 00 20 00 20 00 . . . . . . . . backtrace: [<c006f74b>] __save_stack_trace+0x17/0x1c [<c006f81d>] create_object+0xcd/0x188 [<c01f5457>] kmemleak_alloc+0x1b/0x3c [<c006e303>] __kmalloc+0xdb/0xe8 [<c012cc4b>] vc_do_resize+0x73/0x1e0 [<c012cdf1>] vc_resize+0x15/0x18 [<c011afc1>] fbcon_init+0x1f9/0x2b8 [<c0129e87>] visual_init+0x9f/0xdc [<c012aff3>] vc_allocate+0x7f/0xfc [<c012b087>] con_open+0x17/0x80 [<c0120e43>] tty_open+0x1f7/0x2e4 [<c0072fa1>] chrdev_open+0x101/0x118 [<c006ffad>] __dentry_open+0x105/0x1cc [<c00700fd>] nameidata_to_filp+0x2d/0x38 [<c00788cd>] do_filp_open+0x2c1/0x54c [<c006fdff>] do_sys_open+0x3b/0xb4 Reported-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Krzysztof Helt <krzysztof.h1@poczta.fm> Tested-by: Dave Young <hidave.darkstar@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/video/console/fbcon.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index 471a9a6..3a44695 100644
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -1082,7 +1082,6 @@ static void fbcon_init(struct vc_data *vc, int init)
new_rows = FBCON_SWAP(ops->rotate, info->var.yres, info->var.xres);
new_cols /= vc->vc_font.width;
new_rows /= vc->vc_font.height;
- vc_resize(vc, new_cols, new_rows);
/*
* We must always set the mode. The mode of the previous console
@@ -1111,10 +1110,11 @@ static void fbcon_init(struct vc_data *vc, int init)
* vc_{cols,rows}, but we must not set those if we are only
* resizing the console.
*/
- if (!init) {
+ if (init) {
vc->vc_cols = new_cols;
vc->vc_rows = new_rows;
- }
+ } else
+ vc_resize(vc, new_cols, new_rows);
if (logo)
fbcon_prepare_logo(vc, info, cols, rows, new_cols, new_rows);
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