linux-toradex.git/fs/proc, branch v2.6.31.3

Fix idle time field in /proc/uptime

2009-10-05T16:33:01+00:00

commit 96830a57de1197519b62af6a4c9ceea556c18c3d upstream.

Git commit 79741dd changes idle cputime accounting, but unfortunately
the /proc/uptime file hasn't caught up.  Here the idle time calculation
from /proc/stat is copied over.

Signed-off-by: Michael Abbott 
Signed-off-by: Martin Schwidefsky 
Signed-off-by: Greg Kroah-Hartman

/proc/kcore: work around a BUG()

2009-10-05T16:32:54+00:00

Not upstream due to other fixes in .32


Works around a BUG() which is triggered when the kernel accesses holes in
vmalloc regions.

BUG: unable to handle kernel paging request at fa54c000
IP: [] read_kcore+0x260/0x31a
*pde = 3540b067 *pte = 00000000
Oops: 0000 [#1] SMP
last sysfs file: /sys/devices/pci0000:00/0000:00:1c.2/0000:03:00.0/ieee80211/phy0/rfkill0/state
Modules linked in: fuse sco bridge stp llc bnep l2cap bluetooth sunrpc nf_conntrack_ftp ip6t_REJECT nf_conntrack_ipv6 ip6table_filter ip6_tables ipv6 cpufreq_ondemand acpi_cpufreq dm_multipath uinput usb_storage arc4 ecb snd_hda_codec_realtek snd_hda_intel ath5k snd_hda_codec snd_hwdep iTCO_wdt snd_pcm iTCO_vendor_support pcspkr i2c_i801 mac80211 joydev snd_timer serio_raw r8169 snd soundcore mii snd_page_alloc ath cfg80211 ata_generic i915 drm i2c_algo_bit i2c_core video output [last unloaded: scsi_wait_scan]
Sep  4 12:45:16 tuxedu kernel: Pid: 2266, comm: cat Not tainted (2.6.31-rc8 #2) Joybook Lite U101
EIP: 0060:[] EFLAGS: 00010286 CPU: 0
EIP is at read_kcore+0x260/0x31a
EAX: f5e5ea00 EBX: fa54d000 ECX: 00000400 EDX: 00001000
ESI: fa54c000 EDI: f44ad000 EBP: e4533f4c ESP: e4533f24
DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Process cat (pid: 2266, ti=e4532000 task=f09d19a0 task.ti=e4532000)
Stack:
00005000 00000000 f44ad000 09d9c000 00003000 fa54c000 00001000 f6d16f60
 e4520b80 fffffffb e4533f70 c04ef8eb e4533f98 00008000 09d97000 c04f661a
 e4520b80 09d97000 c04ef88c e4533f8c c04ba531 e4533f98 c04c0930 e4520b80
Call Trace:
[] ? proc_reg_read+0x5f/0x73
[] ? read_kcore+0x0/0x31a
[] ? proc_reg_read+0x0/0x73
[] ? vfs_read+0x82/0xe1
[] ? path_put+0x1a/0x1d
[] ? sys_read+0x40/0x62
[] ? sysenter_do_call+0x12/0x2d
Code: 39 f3 89 ca 0f 43 f3 89 fb 29 f2 29 f3 39 cf 0f 46 d3 29 55 dc 8d 1c 32 f6 40 0c 01 75 18 89 d1 89 f7 c1 e9 02 2b 7d ec 03 7d e0  a5 89 d1 83 e1 03 74 02 f3 a4 8b 00 83 7d dc 00 74 04 85 c0
EIP: [] read_kcore+0x260/0x31a SS:ESP 0068:e4533f24
CR2: 00000000fa54c000


To access vmalloc area which may have memory holes, copy_from_user is
useful.  So this:

 # cat /proc/kcore > /dev/null

will not panic.

This is a minimal fix, suitable for 2.6.30.x and 2.6.31.  More extensive
/proc/kcore changes are planned for 2.6.32.

Signed-off-by: KAMEZAWA Hiroyuki 
Tested-by: Nick Craig-Wood 
Cc: Pekka Enberg 
Reported-by: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

mm: revert "oom: move oom_adj value"

2009-08-18T23:31:13+00:00

The commit 2ff05b2b (oom: move oom_adj value) moveed the oom_adj value to
the mm_struct.  It was a very good first step for sanitize OOM.

However Paul Menage reported the commit makes regression to his job
scheduler.  Current OOM logic can kill OOM_DISABLED process.

Why? His program has the code of similar to the following.

	...
	set_oom_adj(OOM_DISABLE); /* The job scheduler never killed by oom */
	...
	if (vfork() == 0) {
		set_oom_adj(0); /* Invoked child can be killed */
		execve("foo-bar-cmd");
	}
	....

vfork() parent and child are shared the same mm_struct.  then above
set_oom_adj(0) doesn't only change oom_adj for vfork() child, it's also
change oom_adj for vfork() parent.  Then, vfork() parent (job scheduler)
lost OOM immune and it was killed.

Actually, fork-setting-exec idiom is very frequently used in userland program.
We must not break this assumption.

Then, this patch revert commit 2ff05b2b and related commit.

Reverted commit list
---------------------
- commit 2ff05b2b4e (oom: move oom_adj value from task_struct to mm_struct)
- commit 4d8b9135c3 (oom: avoid unnecessary mm locking and scanning for OOM_DISABLE)
- commit 8123681022 (oom: only oom kill exiting tasks with attached memory)
- commit 933b787b57 (mm: copy over oom_adj value at fork time)

Signed-off-by: KOSAKI Motohiro 
Cc: Paul Menage 
Cc: David Rientjes 
Cc: KAMEZAWA Hiroyuki 
Cc: Rik van Riel 
Cc: Linus Torvalds 
Cc: Oleg Nesterov 
Cc: Nick Piggin 
Cc: Mel Gorman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm_for_maps: take ->cred_guard_mutex to fix the race with exec

2009-08-10T10:49:26+00:00

The problem is minor, but without ->cred_guard_mutex held we can race
with exec() and get the new ->mm but check old creds.

Now we do not need to re-check task->mm after ptrace_may_access(), it
can't be changed to the new mm under us.

Strictly speaking, this also fixes another very minor problem. Unless
security check fails or the task exits mm_for_maps() should never
return NULL, the caller should get either old or new ->mm.

Signed-off-by: Oleg Nesterov 
Acked-by: Serge Hallyn 
Signed-off-by: James Morris

mm_for_maps: shift down_read(mmap_sem) to the caller

2009-08-10T10:48:32+00:00

mm_for_maps() takes ->mmap_sem after security checks, this looks
strange and obfuscates the locking rules. Move this lock to its
single caller, m_start().

Signed-off-by: Oleg Nesterov 
Acked-by: Serge Hallyn 
Signed-off-by: James Morris

mm_for_maps: simplify, use ptrace_may_access()

2009-08-10T10:47:42+00:00

It would be nice to kill __ptrace_may_access(). It requires task_lock(),
but this lock is only needed to read mm->flags in the middle.

Convert mm_for_maps() to use ptrace_may_access(), this also simplifies
the code a little bit.

Also, we do not need to take ->mmap_sem in advance. In fact I think
mm_for_maps() should not play with ->mmap_sem at all, the caller should
take this lock.

With or without this patch, without ->cred_guard_mutex held we can race
with exec() and get the new ->mm but check old creds.

Signed-off-by: Oleg Nesterov 
Reviewed-by: Serge Hallyn 
Signed-off-by: James Morris

proc: vmcore - use kzalloc in get_new_element()

2009-06-18T20:03:41+00:00

Instead of kmalloc+memset better use straight kzalloc

Signed-off-by: Cyrill Gorcunov 
Reviewed-by: WANG Cong 
Acked-by: Vivek Goyal 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

procfs: remove sparse errors in proc_devtree.c

2009-06-18T20:03:41+00:00

CHECK   fs/proc/proc_devtree.c
fs/proc/proc_devtree.c:197:14: warning: Using plain integer as NULL pointer
fs/proc/proc_devtree.c:203:34: warning: Using plain integer as NULL pointer
fs/proc/proc_devtree.c:210:14: warning: Using plain integer as NULL pointer
fs/proc/proc_devtree.c:223:26: warning: Using plain integer as NULL pointer
fs/proc/proc_devtree.c:226:14: warning: Using plain integer as NULL pointer

Signed-off-by: Michal Simek 
Cc: Alexey Dobriyan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

proc: export statistics for softirq to /proc

2009-06-18T20:03:41+00:00

Export statistics for softirq in /proc/softirqs and /proc/stat.

1. /proc/softirqs
Implement /proc/softirqs which shows the number of softirq
for each CPU like /proc/interrupts.

2. /proc/stat
Add the "softirq" line to /proc/stat.
This line shows the number of softirq for all cpu.
The first column is the total of all softirqs and
each subsequent column is the total for particular softirq.

[kosaki.motohiro@jp.fujitsu.com: remove redundant for_each_possible_cpu() loop]
Signed-off-by: Keika Kobayashi 
Reviewed-by: Hiroshi Shimamoto 
Cc: KOSAKI Motohiro 
Cc: Ingo Molnar 
Cc: Eric Dumazet 
Cc: Alexey Dobriyan 
Signed-off-by: KOSAKI Motohiro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

oom: move oom_adj value from task_struct to mm_struct

2009-06-17T02:47:43+00:00

The per-task oom_adj value is a characteristic of its mm more than the
task itself since it's not possible to oom kill any thread that shares the
mm.  If a task were to be killed while attached to an mm that could not be
freed because another thread were set to OOM_DISABLE, it would have
needlessly been terminated since there is no potential for future memory
freeing.

This patch moves oomkilladj (now more appropriately named oom_adj) from
struct task_struct to struct mm_struct.  This requires task_lock() on a
task to check its oom_adj value to protect against exec, but it's already
necessary to take the lock when dereferencing the mm to find the total VM
size for the badness heuristic.

This fixes a livelock if the oom killer chooses a task and another thread
sharing the same memory has an oom_adj value of OOM_DISABLE.  This occurs
because oom_kill_task() repeatedly returns 1 and refuses to kill the
chosen task while select_bad_process() will repeatedly choose the same
task during the next retry.

Taking task_lock() in select_bad_process() to check for OOM_DISABLE and in
oom_kill_task() to check for threads sharing the same memory will be
removed in the next patch in this series where it will no longer be
necessary.

Writing to /proc/pid/oom_adj for a kthread will now return -EINVAL since
these threads are immune from oom killing already.  They simply report an
oom_adj value of OOM_DISABLE.

Cc: Nick Piggin 
Cc: Rik van Riel 
Cc: Mel Gorman 
Signed-off-by: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds