[2.6.33-rc7] tty: page allocation failure (from tty_buffer_request_room)
From: Henry Nestler
Date: Fri Feb 12 2010 - 18:31:10 EST
Subject line changed to more the relevant informations, and CC to tty
maintainer.
Simon found the same bug on 2.6.31-1-powerpc:
http://www.mail-archive.com/debian-bugs-dist@xxxxxxxxxxxxxxxx/msg715324.html
I can form a patch for kernel 2.6.33-rc7. But I don't know it is right,
that tty_buffer_request_room calls kmalloc (over tty_buffer_find -->
tty_buffer_alloc) from inside a spin_lock? Think yes, because
tty_buffer_find needs the lock.
Henry
I got the following twice with 2.6.33-rc7. Henry Nestler
(coLinux maintainer) thinks it may also happen without coLinux,
so I'm redirecting it.
---------- Forwarded message ----------
Hello Frédéric,
I think that warning is abundant.
You are doing some output on console, for example write to a device /dev/tty.
Inside tty_buffer_request_room I found, that kmalloc was called and interrupts
are disabled. That means, memory can not swap out - if no free page is
available. tty_buffer_request_room checks for NULL returns. So, it assumes,
that kmalloc can fail. Unless they have forgotten to set __GFP_NOWARN. - Or it
is a defective design, and kmalloc should not called inside a spin_lock.
This depends on low system memory system, and I think, it can be have also in
native kernel. (without colinux patch)
Your warning output should send to kernel list.
For coLinux I will suppress the warning in this way:
===
--- linux-2.6.33-rc7-source/drivers/char/tty_buffer.c
+++ linux-2.6.33-rc7-source/drivers/char/tty_buffer.c
@@ -60,7 +60,7 @@
if (tty->buf.memory_used + size > 65536)
return NULL;
- p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC);
+ p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC | __GFP_NOWARN);
if (p == NULL)
return NULL;
p->used = 0;
===
-- Henry
[... non informative text removed ...]
At 12.02.2010 05:47, Frédéric L. W. Meunier wrote:
Hi Henry. I found the following in my /var/log/kernel. I didn't
notice anything at the time, and don't remember what I was
doing (if anything).
kernel: mconf: page allocation failure. order:1, mode:0x20
kernel: Pid: 25277, comm: mconf Not tainted 2.6.33-rc7-co #1
kernel: Call Trace:
kernel: [<c1184ed7>] ? printk+0xf/0x18
kernel: [<c1042a8e>] __alloc_pages_nodemask+0x3e8/0x467
kernel: [<c105b251>] cache_alloc_refill+0x269/0x454
kernel: [<c10118c8>] ? try_to_wake_up+0x165/0x181
kernel: [<c105b49f>] __kmalloc+0x63/0x93
kernel: [<c1107163>] tty_buffer_request_room+0xae/0x12c
kernel: [<c11072ee>] tty_insert_flip_string+0x26/0x70
kernel: [<c1107e18>] pty_write+0x28/0x49
kernel: [<c1103be6>] n_tty_write+0x1df/0x2c8
kernel: [<c10118e4>] ? default_wake_function+0x0/0xd
kernel: [<c110189f>] tty_write+0x153/0x1c9
kernel: [<c104e6d4>] ? handle_mm_fault+0x227/0x4cf
kernel: [<c1103a07>] ? n_tty_write+0x0/0x2c8
kernel: [<c105dda9>] vfs_write+0x8a/0x112
kernel: [<c110174c>] ? tty_write+0x0/0x1c9
kernel: [<c105dec8>] sys_write+0x3b/0x60
kernel: [<c1002650>] sysenter_do_call+0x12/0x26
kernel: Mem-Info:
kernel: Normal per-cpu:
kernel: CPU 0: hi: 90, btch: 15 usd: 15
kernel: active_anon:4096 inactive_anon:6585 isolated_anon:0
kernel: active_file:22030 inactive_file:21094 isolated_file:0
kernel: unevictable:0 dirty:66 writeback:0 unstable:0
kernel: free:525 slab_reclaimable:4787 slab_unreclaimable:557
kernel: mapped:2518 shmem:286 pagetables:179 bounce:0
kernel: Normal free:2100kB min:2036kB low:2544kB high:3052kB active_anon:16384kB inactive_anon:26340kB active_file:88120kB inactive_file:84376kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:260096kB mlocked:0kB dirty:264kB writeback:0kB mapped:10072kB shmem:1144kB slab_reclaimable:19148kB slab_unreclaimable:2228kB kernel_stack:352kB pagetables:716kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:5 all_unreclaimable? no
kernel: lowmem_reserve[]: 0 0
kernel: Normal: 497*4kB 2*8kB 6*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 2100kB
kernel: 43443 total pagecache pages
kernel: 26 pages in swap cache
kernel: Swap cache stats: add 122, delete 96, find 7/8
kernel: Free swap = 987512kB
kernel: Total swap = 987956kB
kernel: 65536 pages RAM
kernel: 5438 pages reserved
kernel: 32537 pages shared
kernel: 31318 pages non-shared
kernel: mconf: page allocation failure. order:1, mode:0x20
--
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