Neil Horman
a06a4dc3a0
kmod: add init function to usermodehelper ...
About 6 months ago, I made a set of changes to how the core-dump-to-a-pipe
feature in the kernel works. We had reports of several races, including
some reports of apps bypassing our recursion check so that a process that
was forked as part of a core_pattern setup could infinitely crash and
refork until the system crashed.
We fixed those by improving our recursion checks. The new check basically
refuses to fork a process if its core limit is zero, which works well.
Unfortunately, I've been getting grief from maintainer of user space
programs that are inserted as the forked process of core_pattern. They
contend that in order for their programs (such as abrt and apport) to
work, all the running processes in a system must have their core limits
set to a non-zero value, to which I say 'yes'. I did this by design, and
think thats the right way to do things.
But I've been asked to ease this burden on user space enough times that I
thought I would take a look at it. The first suggestion was to make the
recursion check fail on a non-zero 'special' number, like one. That way
the core collector process could set its core size ulimit to 1, and enable
the kernel's recursion detection. This isn't a bad idea on the surface,
but I don't like it since its opt-in, in that if a program like abrt or
apport has a bug and fails to set such a core limit, we're left with a
recursively crashing system again.
So I've come up with this. What I've done is modify the
call_usermodehelper api such that an extra parameter is added, a function
pointer which will be called by the user helper task, after it forks, but
before it exec's the required process. This will give the caller the
opportunity to get a call back in the processes context, allowing it to do
whatever it needs to to the process in the kernel prior to exec-ing the
user space code. In the case of do_coredump, this callback is ues to set
the core ulimit of the helper process to 1. This elimnates the opt-in
problem that I had above, as it allows the ulimit for core sizes to be set
to the value of 1, which is what the recursion check looks for in
do_coredump.
This patch:
Create new function call_usermodehelper_fns() and allow it to assign both
an init and cleanup function, as we'll as arbitrary data.
The init function is called from the context of the forked process and
allows for customization of the helper process prior to calling exec. Its
return code gates the continuation of the process, or causes its exit.
Also add an arbitrary data pointer to the subprocess_info struct allowing
for data to be passed from the caller to the new process, and the
subsequent cleanup process
Also, use this patch to cleanup the cleanup function. It currently takes
an argp and envp pointer for freeing, which is ugly. Lets instead just
make the subprocess_info structure public, and pass that to the cleanup
and init routines
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:44 -07:00
x86, kgdb, init: Add early and late debug states
2010-05-20 21:04:29 -05:00
genirq: Clear CPU mask in affinity_hint when none is provided
2010-05-12 11:23:34 +02:00
PM / Hibernate: Fix block_io.c printk warning
2010-05-10 23:08:18 +02:00
Merge branch 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2010-05-19 17:11:10 -07:00
Merge branch 'master' into for-2.6.35
2010-05-21 21:27:26 +02:00
Merge branch 'next' into for-linus
2010-05-18 08:57:00 +10:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
audit: preface audit printk with audit
2010-04-05 13:19:45 -07:00
kbuild: move bounds.h to include/generated
2009-12-12 13:08:14 +01:00
sched: Remove remaining USER_SCHED code
2010-04-02 20:12:00 +02:00
cgroups: make cftype.unregister_event() void-returning
2010-05-27 09:12:44 -07:00
Freezer / cgroup freezer: Update stale locking comments
2010-05-10 23:18:47 +02:00
cpumask: fix compat getaffinity
2010-05-19 11:48:18 -07:00
mem-hotplug: fix potential race while building zonelist for new populated zone
2010-05-25 08:07:02 -07:00
cpusets: new round-robin rotor for SLAB allocations
2010-05-27 09:12:44 -07:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6
2010-05-20 08:55:50 -07:00
x86: Do not free zero sized per cpu areas
2010-03-29 18:55:40 +02:00
elf coredump: add extended numbering support
2010-03-06 11:26:46 -08:00
cpuset,mm: fix no node to alloc memory when changing cpuset's mems
2010-05-25 08:06:57 -07:00
cpusets: randomize node rotor used in cpuset_mem_spread_node()
2010-05-27 09:12:44 -07:00
futex: Handle futex value corruption gracefully
2010-02-03 15:13:22 +01:00
futex: Protect pid lookup in compat code with RCU
2009-12-09 14:22:14 +01:00
security: remove dead hook task_setgroups
2010-04-12 12:19:18 +10:00
hrtimers: Provide schedule_hrtimeout for CLOCK_REALTIME
2010-04-06 21:50:03 +02:00
softlockup: Fix hung_task_check_count sysctl
2009-11-27 06:21:57 +01:00
hw_breakpoints: Fix percpu build failure
2010-05-04 08:39:36 +02:00
itimers: Fix racy writes to cpu_itimer fields
2009-11-18 16:32:12 +01:00
kdb: core for kgdb back end (2 of 2)
2010-05-20 21:04:21 -05:00
mutex: Better control mutex adaptive spinning config
2009-12-03 11:50:11 +01:00
kexec: fix OOPS in crash_kernel_shrink
2010-05-11 17:33:42 -07:00
kfifo: Don't use integer as NULL pointer
2010-02-16 15:11:08 -08:00
kmod: add init function to usermodehelper
2010-05-27 09:12:44 -07:00
kprobes: Move enable/disable_kprobe() out from debugfs code
2010-05-08 18:08:30 +02:00
sysfs: add struct file* to bin_attr callbacks
2010-05-21 09:37:31 -07:00
cpuset: fix the problem that cpuset_mem_spread_node() returns an offline node
2010-03-24 16:31:21 -07:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
lockdep: Add novalidate class for dev->mutex conversion
2010-05-21 09:37:30 -07:00
lockdep: No need to disable preemption in debug atomic ops
2010-05-04 05:38:16 +02:00
lockstat: Make lockstat counting per cpu
2010-04-06 00:15:37 +02:00
Move kernel/kgdb.c to kernel/debug/debug_core.c
2010-05-20 21:04:18 -05:00
Revert "module: drop the lock while waiting for module to complete initialization."
2010-05-25 16:48:30 -07:00
locking: Implement new raw_spinlock
2009-12-14 23:55:32 +01:00
mutex: Better control mutex adaptive spinning config
2009-12-03 11:50:11 +01:00
sched: Use lockdep-based checking on rcu_dereference()
2010-02-25 10:34:26 +01:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
padata: Use get_online_cpus/put_online_cpus in padata_free
2010-05-19 13:45:35 +10:00
panic: Add taint flag TAINT_FIRMWARE_WORKAROUND ('I')
2010-05-19 08:37:43 +01:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
2010-03-12 16:04:50 -08:00
perf: Fix exit() vs event-groups
2010-05-11 17:08:24 +02:00
Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2010-03-13 14:43:01 -08:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
PM: PM QOS update fix
2010-05-17 00:21:03 +02:00
posix-cpu-timers: Optimize run_posix_cpu_timers()
2010-05-10 14:24:26 +02:00
posix-timers.c: Don't export local functions
2010-02-05 14:54:10 +01:00
printk,kdb: capture printk() when in kdb shell
2010-05-20 21:04:27 -05:00
profile: fix stats and data leakage
2010-05-14 19:45:06 -07:00
ptrace: PTRACE_GETFDPIC: fix the unsafe usage of child->mm
2010-05-27 09:12:44 -07:00
x86: Change range end to start+size
2010-02-10 17:47:17 -08:00
rcu: slim down rcutiny by removing rcu_scheduler_active and friends
2010-05-10 11:08:34 -07:00
rcu: remove all rcu head initializations, except on_stack initializations
2010-05-11 16:10:47 -07:00
rcu: slim down rcutiny by removing rcu_scheduler_active and friends
2010-05-10 11:08:34 -07:00
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2010-05-18 08:27:54 -07:00
rcu: remove all rcu head initializations, except on_stack initializations
2010-05-11 16:10:47 -07:00
rcu: reduce the number of spurious RCU_SOFTIRQ invocations
2010-05-10 11:08:35 -07:00
rcu: remove all rcu head initializations, except on_stack initializations
2010-05-11 16:10:47 -07:00
rcu: reduce the number of spurious RCU_SOFTIRQ invocations
2010-05-10 11:08:35 -07:00
pipe: add support for shrinking and growing pipes
2010-05-21 21:12:40 +02:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
resource: shared I/O region support
2010-05-11 12:01:10 -07:00
sched: Convert pi_lock to raw_spinlock
2009-12-14 23:55:33 +01:00
rtmutes: Convert rtmutex.lock to raw_spinlock
2009-12-14 23:55:33 +01:00
Merge branch 'kdb-merge' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb
2010-05-21 11:08:05 -07:00
blkio: fix for modular blk-cgroup build
2010-04-15 08:54:59 +02:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
sched: Convert cpupri lock to raw_spinlock
2009-12-14 23:55:33 +01:00
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2010-05-18 08:27:54 -07:00
sched: replace migration_thread with cpu_stop
2010-05-06 18:49:21 +02:00
sched: Remove ASYM_GRAN feature
2010-03-11 18:32:53 +01:00
sched: Cure load average vs NO_HZ woes
2010-04-23 11:02:02 +02:00
sched: Add enqueue/dequeue flags
2010-04-02 20:12:05 +02:00
signals: check_kill_permission(): don't check creds if same_thread_group()
2010-05-27 09:12:44 -07:00
SLOW_WORK: Move slow_work's proc file to debugfs
2009-12-01 08:20:31 -08:00
slow-work: use get_ref wrapper instead of directly calling get_ref
2010-03-29 09:13:30 -07:00
SLOW_WORK: CONFIG_SLOW_WORK_PROC should be CONFIG_SLOW_WORK_DEBUG
2010-03-29 09:14:47 -07:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
rcu: refactor RCU's context-switch handling
2010-05-10 11:08:33 -07:00
softlockup: Stop spurious softlockup messages due to overflow
2010-03-21 19:30:13 +01:00
locking: Cleanup the name space completely
2009-12-14 23:55:33 +01:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
stop_machine: Move local variable closer to the usage site in cpu_stop_cpu_callback()
2010-05-18 00:17:44 +02:00
kmod: add init function to usermodehelper
2010-05-27 09:12:44 -07:00
Add generic sys_ipc wrapper
2010-03-12 15:52:32 -08:00
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6
2010-05-25 16:59:51 -07:00
sysctl: don't use own implementation of hex_to_bin()
2010-05-25 08:07:05 -07:00
ipv4 05/05: add sysctl to accept packets with local source addresses
2009-12-03 12:14:38 -08:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
timekeeping: Fix timezone update
2010-05-24 11:50:38 +02:00
timers: Fix slack calculation for expired timers
2010-05-24 12:10:23 +02:00
mm: clean up mm_counter
2010-03-06 11:26:23 -08:00
core: Clean up user return notifers use of per_cpu
2009-12-02 10:22:59 +01:00
sched: Remove a stale comment
2010-05-10 08:48:39 +02:00
kref: remove kref_set
2010-05-21 09:37:29 -07:00
sysctl kernel: Remove binary sysctl logic
2009-11-12 02:04:55 -08:00
workqueue: change cancel_work_sync() to clear work->data
2010-04-30 08:57:25 +02:00
a06a4dc3a0