The patch titled
vt: printk: Fix framebuffer console triggering might_sleep assertion
has been added to the -mm tree. Its filename is
vt-printk-fix-framebuffer-console-triggering-might_sleep.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: vt: printk: Fix framebuffer console triggering might_sleep assertion
From: "Antonino A. Daplas" <adaplas@xxxxxxxxx>
Reported by: Dave Jones
Whilst printk'ing to both console and serial console, I got this...
(2.6.18rc1)
BUG: sleeping function called from invalid context at kernel/sched.c:4438
in_atomic():0, irqs_disabled():1
Call Trace:
[<ffffffff80271db8>] show_trace+0xaa/0x23d
[<ffffffff80271f60>] dump_stack+0x15/0x17
[<ffffffff8020b9f8>] __might_sleep+0xb2/0xb4
[<ffffffff8029232e>] __cond_resched+0x15/0x55
[<ffffffff80267eb8>] cond_resched+0x3b/0x42
[<ffffffff80268c64>] console_conditional_schedule+0x12/0x14
[<ffffffff80368159>] fbcon_redraw+0xf6/0x160
[<ffffffff80369c58>] fbcon_scroll+0x5d9/0xb52
[<ffffffff803a43c4>] scrup+0x6b/0xd6
[<ffffffff803a4453>] lf+0x24/0x44
[<ffffffff803a7ff8>] vt_console_print+0x166/0x23d
[<ffffffff80295528>] __call_console_drivers+0x65/0x76
[<ffffffff80295597>] _call_console_drivers+0x5e/0x62
[<ffffffff80217e3f>] release_console_sem+0x14b/0x232
[<ffffffff8036acd6>] fb_flashcursor+0x279/0x2a6
[<ffffffff80251e3f>] run_workqueue+0xa8/0xfb
[<ffffffff8024e5e0>] worker_thread+0xef/0x122
[<ffffffff8023660f>] kthread+0x100/0x136
[<ffffffff8026419e>] child_rip+0x8/0x12
This can occur when release_console_sem() is called but the log
buffer still has contents that need to be flushed. The console drivers
are called while the console_may_schedule flag is still true. The
might_sleep() is triggered when fbcon calls console_conditional_schedule().
Fix by setting console_may_schedule to zero earlier, before the call to the
console drivers.
Signed-off-by: Antonino Daplas <adaplas@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
kernel/printk.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff -puN kernel/printk.c~vt-printk-fix-framebuffer-console-triggering-might_sleep kernel/printk.c
--- a/kernel/printk.c~vt-printk-fix-framebuffer-console-triggering-might_sleep
+++ a/kernel/printk.c
@@ -799,6 +799,9 @@ void release_console_sem(void)
up(&secondary_console_sem);
return;
}
+
+ console_may_schedule = 0;
+
for ( ; ; ) {
spin_lock_irqsave(&logbuf_lock, flags);
wake_klogd |= log_start - log_end;
@@ -812,7 +815,6 @@ void release_console_sem(void)
local_irq_restore(flags);
}
console_locked = 0;
- console_may_schedule = 0;
up(&console_sem);
spin_unlock_irqrestore(&logbuf_lock, flags);
if (wake_klogd && !oops_in_progress && waitqueue_active(&log_wait)) {
_
Patches currently in -mm which might be from adaplas@xxxxxxxxx are
fbdev-statically-link-the-framebuffer-notification-functions.patch
vt-printk-fix-framebuffer-console-triggering-might_sleep.patch
nvidiafb-use-generic-ddc-reading.patch
rivafb-use-generic-ddc-reading.patch
i810fb-use-generic-ddc-reading.patch
savagefb-use-generic-ddc-reading.patch
-
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