fbcon_set_all_vcs: fix kernel crash when switching the rotated consoles
Oleg Nesterov [Thu, 16 Oct 2008 05:03:57 +0000 (22:03 -0700)]
echo 3 >> /sys/class/graphics/fbcon/rotate_all, then switch to another
console. Result:

BUG: unable to handle kernel paging request at ffffc20005d00000
IP: [bitfill_aligned+149/265] bitfill_aligned+0x95/0x109
PGD 7e228067 PUD 7e229067 PMD 7bc1f067 PTE 0
Oops: 0002 [1] SMP
CPU 1
Modules linked in: [...a lot...]
Pid: 10, comm: events/1 Not tainted 2.6.26.5-45.fc9.x86_64 #1
RIP: 0010:[bitfill_aligned+149/265]  [bitfill_aligned+149/265] bitfill_aligned+0x95/0x109
RSP: 0018:ffff81007d811bc8  EFLAGS: 00010216
RAX: ffffc20005d00000 RBX: 0000000000000000 RCX: 0000000000000400
RDX: 0000000000000000 RSI: ffffc20005d00000 RDI: ffffffffffffffff
RBP: ffff81007d811be0 R08: 0000000000000400 R09: 0000000000000040
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000010000
R13: ffffffff811632f0 R14: 0000000000000006 R15: ffff81007cb85400
FS:  0000000000000000(0000) GS:ffff81007e004780(0000) knlGS:0000000000000000
CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: ffffc20005d00000 CR3: 0000000000201000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process events/1 (pid: 10, threadinfo ffff81007d810000, task ffff81007d808000)
Stack:  ffff81007c9d75a0 0000000000000000 0000000000000000 ffff81007d811c80
 ffffffff81163a61 ffff810000000000 ffffffff8115f9c8 0000001000000000
 0000000100aaaaaa 000000007cd0d4a0 fffffd8a00000800 0001000000000000
Call Trace:
 [cfb_fillrect+523/798] cfb_fillrect+0x20b/0x31e
 [soft_cursor+416/436] ? soft_cursor+0x1a0/0x1b4
 [ccw_clear_margins+205/263] ccw_clear_margins+0xcd/0x107
 [fbcon_clear_margins+59/61] fbcon_clear_margins+0x3b/0x3d
 [fbcon_switch+1291/1466] fbcon_switch+0x50b/0x5ba
 [redraw_screen+261/481] redraw_screen+0x105/0x1e1
 [ccw_cursor+0/1869] ? ccw_cursor+0x0/0x74d
 [complete_change_console+48/190] complete_change_console+0x30/0xbe
 [change_console+115/120] change_console+0x73/0x78
 [console_callback+0/292] ? console_callback+0x0/0x124
 [console_callback+97/292] console_callback+0x61/0x124
 [schedule_delayed_work+25/30] ? schedule_delayed_work+0x19/0x1e
 [run_workqueue+139/282] run_workqueue+0x8b/0x11a
 [worker_thread+221/238] worker_thread+0xdd/0xee
 [autoremove_wake_function+0/56] ? autoremove_wake_function+0x0/0x38
 [worker_thread+0/238] ? worker_thread+0x0/0xee
 [kthread+73/118] kthread+0x49/0x76
 [child_rip+10/18] child_rip+0xa/0x12
 [kthread+0/118] ? kthread+0x0/0x76
 [child_rip+0/18] ? child_rip+0x0/0x12

Because fbcon_set_all_vcs()->FBCON_SWAP() uses display->rotate == 0 instead
of fbcon_ops->rotate, and vc_resize() has no effect because it is called with
new_cols/rows == ->vc_cols/rows.

Tested on 2.6.26.5-45.fc9.x86_64, but
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git seems to
have the same problem.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Cc: <stable@kernel.org> [2.6.27.x, 2.6.26.x, maybe 2.6.25.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/video/console/fbcon.c

index da91bb1..93a080e 100644 (file)
@@ -2977,8 +2977,8 @@ static void fbcon_set_all_vcs(struct fb_info *info)
                p = &fb_display[vc->vc_num];
                set_blitting_type(vc, info);
                var_to_display(p, &info->var, info);
-               cols = FBCON_SWAP(p->rotate, info->var.xres, info->var.yres);
-               rows = FBCON_SWAP(p->rotate, info->var.yres, info->var.xres);
+               cols = FBCON_SWAP(ops->rotate, info->var.xres, info->var.yres);
+               rows = FBCON_SWAP(ops->rotate, info->var.yres, info->var.xres);
                cols /= vc->vc_font.width;
                rows /= vc->vc_font.height;
                vc_resize(vc, cols, rows);