Merge third batch of fixes from Andrew Morton:
"Most of the rest. I still have two large patchsets against AIO and
IPC, but they're a bit stuck behind other trees and I'm about to
vanish for six days.
- random fixlets
- inotify
- more of the MM queue
- show_stack() cleanups
- DMI update
- kthread/workqueue things
- compat cleanups
- epoll udpates
- binfmt updates
- nilfs2
- hfs
- hfsplus
- ptrace
- kmod
- coredump
- kexec
- rbtree
- pids
- pidns
- pps
- semaphore tweaks
- some w1 patches
- relay updates
- core Kconfig changes
- sysrq tweaks"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (109 commits)
Documentation/sysrq: fix inconstistent help message of sysrq key
ethernet/emac/sysrq: fix inconstistent help message of sysrq key
sparc/sysrq: fix inconstistent help message of sysrq key
powerpc/xmon/sysrq: fix inconstistent help message of sysrq key
ARM/etm/sysrq: fix inconstistent help message of sysrq key
power/sysrq: fix inconstistent help message of sysrq key
kgdb/sysrq: fix inconstistent help message of sysrq key
lib/decompress.c: fix initconst
notifier-error-inject: fix module names in Kconfig
kernel/sys.c: make prctl(PR_SET_MM) generally available
UAPI: remove empty Kbuild files
menuconfig: print more info for symbol without prompts
init/Kconfig: re-order CONFIG_EXPERT options to fix menuconfig display
kconfig menu: move Virtualization drivers near other virtualization options
Kconfig: consolidate CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
relay: use macro PAGE_ALIGN instead of FIX_SIZE
kernel/relay.c: move FIX_SIZE macro into relay.c
kernel/relay.c: remove unused function argument actor
drivers/w1/slaves/w1_ds2760.c: fix the error handling in w1_ds2760_add_slave()
drivers/w1/slaves/w1_ds2781.c: fix the error handling in w1_ds2781_add_slave()
...
A mixed bad of little fixes. No real new functionality here.
Several patches are tagged for -stable.
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Merge tag 'md-3.10' of git://neil.brown.name/md
Pull md fixes from NeilBrown:
"A mixed bag of little fixes. No real new functionality here. Several
patches are tagged for -stable."
* tag 'md-3.10' of git://neil.brown.name/md:
MD: ignore discard request for hard disks of hybid raid1/raid10 array
md: bad block list should default to disabled.
md: raid1/raid10 md devices leak memory when stopping
DM RAID: Add message/status support for changing sync action
MD: Export 'md_reap_sync_thread' function
md: don't update metadata when stopping a read-only array.
md: Allow devices to be re-added to a read-only array.
md/raid10: Allow skipping recovery when clean arrays are assembled
MD: Fix typos in MD documentation
md/raid5: avoid an extra write when writing to a known-bad-block.
md/raid5: Change or of some order to improve efficiency.
md: use set_bit_le and clear_bit_le
md: HOT_DISK_REMOVE shouldn't make a read-auto device active.
md: use common code for all calls to ->hot_remove_disk()
md: never update metadata when array is read-only.
Currently help message of /proc/sysrq-trigger highlight its
upper-case characters, like below:
SysRq : HELP : loglevel(0-9) reBoot Crash terminate-all-tasks(E)
memory-full-oom-kill(F) kill-all-tasks(I) ...
this would confuse user trigger sysrq by upper-case character, which is
inconsistent with the real lower-case character registed key.
This inconsistent help message will also lead more confused when
26 upper-case letters put into use in future.
This patch fix sysrq documentation.
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently help message of /proc/sysrq-trigger highlight its upper-case
characters, like below:
SysRq : HELP : loglevel(0-9) reBoot Crash terminate-all-tasks(E)
memory-full-oom-kill(F) kill-all-tasks(I) ...
this would confuse user trigger sysrq by upper-case character, which is
inconsistent with the real lower-case character registed key.
This inconsistent help message will also lead more confused when
26 upper-case letters put into use in future.
This patch ethernet emac sysrq key: "emac(c)"
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Cc: Thadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently help message of /proc/sysrq-trigger highlight its
upper-case characters, like below:
SysRq : HELP : loglevel(0-9) reBoot Crash terminate-all-tasks(E)
memory-full-oom-kill(F) kill-all-tasks(I) ...
this would confuse user trigger sysrq by upper-case character, which is
inconsistent with the real lower-case character registed key.
This inconsistent help message will also lead more confused when
26 upper-case letters put into use in future.
This patch fix spare sysrq key: "global-regs(y)"
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently help message of /proc/sysrq-trigger highlight its
upper-case characters, like below:
SysRq : HELP : loglevel(0-9) reBoot Crash terminate-all-tasks(E)
memory-full-oom-kill(F) kill-all-tasks(I) ...
this would confuse user trigger sysrq by upper-case character, which is
inconsistent with the real lower-case character registed key.
This inconsistent help message will also lead more confused when
26 upper-case letters put into use in future.
This patch fix powerpc xmon sysrq key: "xmon(x)"
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently help message of /proc/sysrq-trigger highlights its
upper-case characters, like below:
SysRq : HELP : loglevel(0-9) reBoot Crash terminate-all-tasks(E)
memory-full-oom-kill(F) kill-all-tasks(I) ...
this would confuse user trigger sysrq by upper-case character, which is
inconsistent with the real lower-case character registed key.
This inconsistent help message will also lead more confused when
26 upper-case letters put into use in future.
This patch fix arm etm sysrq key: "etm-buffer-dump(v)"
(This patch also add "-" to separate each sysrq key help word,
instead of spaces)
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently help message of /proc/sysrq-trigger highlight its
upper-case characters, like below:
SysRq : HELP : loglevel(0-9) reBoot Crash terminate-all-tasks(E)
memory-full-oom-kill(F) kill-all-tasks(I) ...
this would confuse user trigger sysrq by upper-case character, which is
inconsistent with the real lower-case character registed key.
This inconsistent help message will also lead more confused when
26 upper-case letters put into use in future.
This patch fix power off sysrq key: "poweroff(o)"
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently help message of /proc/sysrq-trigger highlight its upper-case
characters, like below:
SysRq : HELP : loglevel(0-9) reBoot Crash terminate-all-tasks(E)
memory-full-oom-kill(F) kill-all-tasks(I) ...
this would confuse user trigger sysrq by upper-case character, which is
inconsistent with the real lower-case character registed key.
This inconsistent help message will also lead more confused when
26 upper-case letters put into use in future.
This patch fix kgdb sysrq key: "debug(g)"
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The Kconfig help text for MEMORY_NOTIFIER_ERROR_INJECT and
OF_RECONFIG_NOTIFIER_ERROR_INJECT has mismatched module names.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The purpose of this patch is to allow privileged processes to set
their own per-memory memory-region fields:
start_code, end_code, start_data, end_data, start_brk, brk,
start_stack, arg_start, arg_end, env_start, env_end.
This functionality is needed by any application or package that needs to
reconstruct Linux processes, that is, to start them in any way other than
by means of an "execve()" from an executable file. This includes:
1. Restoring processes from a checkpoint-file (by all potential
user-level checkpointing packages, not only CRIU's).
2. Restarting processes on another node after process migration.
3. Starting duplicated copies of a running process (for reliability
and high-availablity).
4. Starting a process from an executable format that is not supported
by Linux, thus requiring a "manual execve" by a user-level utility.
5. Similarly, starting a process from a networked and/or crypted
executable that, for confidentiality, licensing or other reasons,
may not be written to the local file-systems.
The code that does that was already included in the Linux kernel by the
CRIU group, in the form of "prctl(PR_SET_MM)", but prior to this was
enclosed within their private "#ifdef CONFIG_CHECKPOINT_RESTORE", which is
normally disabled. The patch removes those ifdefs.
Signed-off-by: Amnon Shiloh <u3557@miso.sublimeip.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove empty Kbuild files as they cause problems with the patch program which
removes files that become empty.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When we search a config symbol, if it has no prompt the position of this
symbol in the Kconfig file and it's dependencies are not printed. This
can be inconvenient, especially when it's set to n and we want to find out
why.
the following is an example:
before:
Symbol: GENERIC_SMP_IDLE_THREAD [=y]
Type : boolean
Selected by: X86 [=y]
after:
Symbol: GENERIC_SMP_IDLE_THREAD [=y]
Type : boolean
Defined at arch/Kconfig:213
Selected by: X86 [=y]
Signed-off-by: Weng Meiling <wengmeiling.weng@huawei.com>
Signed-off-by: Libo Chen <libo.chen@huawei.com>
Cc: Michal Marek <mmarek@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The kconfig language requires that dependent options all follow the
menuconfig symbol in order to be collapsed below it. Recently some hidden
options were added below the EXPERT menuconfig, but did not depend on
EXPERT (because hidden options can't). This broke the display. So
re-order all these options, and while we're here stick the PCI quirks
under the EXPERT menu (since it isn't sitting with any related options).
Before this commit, we get:
[*] Configure standard kernel features (expert users) --->
[ ] Sysctl syscall support
[*] Load all symbols for debugging/ksymoops
...
[ ] Embedded system
Now we get the older (and correct) behavior:
[*] Configure standard kernel features (expert users) --->
[ ] Embedded system
And if you go into the expert menu you get the expert options:
[ ] Sysctl syscall support
[*] Load all symbols for debugging/ksymoops
...
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Michal Marek <mmarek@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make virtualization drivers be logically grouped together (physically
near each other) in the kconfig menu by moving "Virtualization drivers"
to be near "Virtio drivers", Microsort Hyper-V, and Xen driver support.
This is just a user-friendly, visual search change.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Alexander Graf <agraf@suse.de>
Cc: Stuart Yoder <stuart.yoder@freescale.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The help text for this config is duplicated across the x86, parisc, and
s390 Kconfig.debug files. Arnd Bergman noted that the help text was
slightly misleading and should be fixed to state that enabling this
option isn't a problem when using pre 4.4 gcc.
To simplify the rewording, consolidate the text into lib/Kconfig.debug
and modify it there to be more explicit about when you should say N to
this config.
Also, make the text a bit more generic by stating that this option
enables compile time checks so we can cover architectures which emit
warnings vs. ones which emit errors. The details of how an
architecture decided to implement the checks isn't as important as the
concept of compile time checking of copy_from_user() calls.
While we're doing this, remove all the copy_from_user_overflow() code
that's duplicated many times and place it into lib/ so that any
architecture supporting this option can get the function for free.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Helge Deller <deller@gmx.de>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Macro FIX_SIZE is same as PAGE_ALIGN at present, so use PAGE_ALIGN
instead.
Thanks Andrew found this.
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's better to place FIX_SIZE macro in relay.c, instead of relay.h
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently argument `actor' is never used in the relay reading path, so
remove it.
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use platform_device_put() instead of platform_device_unregister() if
platform_device_add() fail, and platform_device_del() should be used in
the error handling case after platform_device_add() success.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Greg KH <greg@kroah.com>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use platform_device_put() instead of platform_device_unregister() if
platform_device_add() fail, and platform_device_del() should be used in
the error handling case after platform_device_add() success.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Greg KH <greg@kroah.com>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use platform_device_put() instead of platform_device_unregister() if
platform_device_add() fail, and platform_device_del() should be used in
the error handling case after platform_device_add() success.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Greg KH <greg@kroah.com>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use platform_device_put() instead of platform_device_unregister() if
platform_device_add() fails, and also add the return value check of
platform_device_add_data().
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Greg KH <greg@kroah.com>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
r592_pm_ops is not exported. Also, CONFIG_PM_SLEEP is used to
remove unnecessary ifdefs.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Cc: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/pps/kc.c:37:1: sparse: symbol 'pps_kc_hardpps_lock' was not declared. Should it be static?
drivers/pps/kc.c:39:19: sparse: symbol 'pps_kc_hardpps_dev' was not declared. Should it be static?
drivers/pps/kc.c:40:5: sparse: symbol 'pps_kc_hardpps_mode' was not declared. Should it be static?
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make CONFIG_PPS_DEBUG and CONFIG_NTP_PPS be hidden if CONFIG_PPS is not
selected, so that we are not prompted for these configuration options if
CONFIG_PPS is not set.
Signed-off-by: Florian Fainelli <florian@openwrt.org>
Cc: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Raise the default max request size for nbd to 128KB (from 127KB) to get it
4KB aligned. This patch also allows the max request size to be increased
(via /sys/block/nbd<x>/queue/max_sectors_kb) to 32MB.
The patch makes nbd network traffic more efficient by:
- reducing request fragmentation (4KB alignment)
- reducing the number of requests (fewer round trips, less network overhead)
Especially in high latency networks, larger request size can make a dramatic
Signed-off-by: Paul Clements <paul.clements@steeleye.com>
Signed-off-by: Michal Belczyk <belczyk@bsd.krakow.pl>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move BITS_PER_PAGE from pid_namespace.c to pid_namespace.h, since we can
simplify the define PID_MAP_ENTRIES by using the BITS_PER_PAGE.
[akpm@linux-foundation.org: kernel/pid.c:54:1: warning: "BITS_PER_PAGE" redefined]
Signed-off-by: Raphael S.Carvalho <raphael.scarv@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
find_next_offset() searches for an available "cleaned bit" in the
respective pid bitmap (page), so returns the offset if found, otherwise
it returns a value equals to BITS_PER_PAGE.
For example, suppose find_next_offset didn't find any available bit, so
there's no purpose to call mk_pid (Wasteful Cpu Cycles).
Therefore, I found it could be better to call mk_pid after the checking
(offset < BITS_PER_PAGE) returned sucessfully! Another point: If (offset
< BITS_PER_PAGE) results in a "failure", then mk_pid would be called
again afterwards.
[akpm@linux-foundation.org: simplify code]
Signed-off-by: Raphael S. Carvalho <raphael.scarv@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Account for the rbtree having 2**bh(v)-1 internal nodes.
While this can be seen as a consequence of other checks, Michel states
that it nicely sums up what the other properties are for.
Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Reviewed-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The types of the following local variables:
- ubytes/mbytes in kimage_load_crash_segment()/kimage_load_normal_segment()
- r in vmcoreinfo_append_str()
are wrong, so fix them.
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Simon Horman <horms@verge.net.au>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
threadgroup_lock() takes signal->cred_guard_mutex to ensure that
thread_group_leader() is stable. This doesn't look nice, the scope of
this lock in do_execve() is huge.
And as Dave pointed out this can lead to deadlock, we have the
following dependencies:
do_execve: cred_guard_mutex -> i_mutex
cgroup_mount: i_mutex -> cgroup_mutex
attach_task_by_pid: cgroup_mutex -> cred_guard_mutex
Change de_thread() to take threadgroup_change_begin() around the
switch-the-leader code and change threadgroup_lock() to avoid
->cred_guard_mutex.
Note that de_thread() can't sleep with ->group_rwsem held, this can
obviously deadlock with the exiting leader if the writer is active, so it
does threadgroup_change_end() before schedule().
Reported-by: Dave Jones <davej@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
set_task_comm() does memset() + wmb() before strlcpy(). This buys
nothing and to add to the confusion, the comment is wrong.
- We do not need memset() to be "safe from non-terminating string
reads", the final char is always zero and we never change it.
- wmb() is paired with nothing, it cannot prevent from printing
the mixture of the old/new data unless the reader takes the lock.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, a write to a procfs file will return the number of bytes
successfully written. If the actual string is longer than this, the
remainder of the string will not be be written and userspace will
complete the operation by issuing additional write()s.
Hence
$ echo -n "abcdefghijklmnopqrs" > /proc/self/comm
results in
$ cat /proc/$$/comm
pqrs
since the final four bytes were written with a second write() since
TASK_COMM_LEN == 16. This is obviously an undesired result and not
equivalent to prctl(PR_SET_NAME). The implementation should not need to
know the definition of TASK_COMM_LEN.
This patch truncates the string to the first TASK_COMM_LEN bytes and
returns the bytes written as the length of the string written so the
second write() is suppressed.
$ cat /proc/$$/comm
abcdefghijklmno
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
wait_for_dump_helpers() calls wake_up/kill_fasync from inside the
wait_event-like loop. This is not needed and in fact this is not
strictly correct, we can/should do this only once after we change
pipe->writers. We could even check if it becomes zero.
Change this code to use use wait_event_interruptible(), this can also
help to make this wait freezable.
With this patch we check pipe->readers without pipe_lock(), this is
fine. Once we see pipe->readers == 1 we know that the handler
decremented the counter, this is all we need.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Neil Horman <nhorman@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
By discussion with Mandeep.
Change dump_write(), dump_seek() and do_coredump() to check
signal_pending() and abort if it is true. dump_seek() does this only
before f_op->llseek(), otherwise it relies on dump_write().
We need this change to ensure that the coredump won't delay suspend, and
to ensure it reacts to SIGKILL "quickly enough", a core dump can take a
lot of time. In particular this can help oom-killer.
We add the new trivial helper, dump_interrupted() to add the comments and
to simplify the potential freezer changes. Perhaps it will have more
callers.
Ideally it should do try_to_freeze() but then we need the unpleasant
changes in dump_write() and wait_for_dump_helpers(). It is not trivial to
change dump_write() to restart if f_op->write() fails because of
freezing(). We need to handle the short writes, we need to clear
TIF_SIGPENDING (and we can't rely on recalc_sigpending() unless we change
it to check PF_DUMPCORE). And if the buggy f_op->write() sets
TIF_SIGPENDING we can not distinguish this case from the race with
freeze_task() + __thaw_task().
So we simply accept the fact that the freezer can truncate a core-dump but
at least you can reliably suspend. Hopefully we can tolerate this
unlikely case and the necessary complications doesn't worth a trouble.
But if we decide to make the coredumping freezable later we can do this on
top of this change.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Neil Horman <nhorman@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that the coredumping process can be SIGKILL'ed, the setting of
->group_exit_code in do_coredump() can race with complete_signal() and
SIGKILL or 0x80 can be "lost", or wait(status) can report status ==
SIGKILL | 0x80.
But the main problem is that it is not clear to me what should we do if
binfmt->core_dump() succeeds but SIGKILL was sent, that is why this patch
comes as a separate change.
This patch adds 0x80 if ->core_dump() succeeds and the process was not
killed. But perhaps we can (should?) re-set ->group_exit_code changed by
SIGKILL back to "siginfo->si_signo |= 0x80" in case when core_dumped == T.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Neil Horman <nhorman@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Roland McGrath <roland@hack.frob.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
prepare_signal() blesses SIGKILL sent to the dumping process but this
signal can be "lost" anyway. The problems is, complete_signal() sees
SIGNAL_GROUP_EXIT and skips the "kill them all" logic. And even if the
dumping process is single-threaded (so the target is always "correct"),
the group-wide SIGKILL is not recorded in task->pending and thus
__fatal_signal_pending() won't be true. A multi-threaded case has even
more problems.
And even ignoring all technical details, SIGNAL_GROUP_EXIT doesn't look
right to me. This coredumping process is not exiting yet, it can do a lot
of work dumping the core.
With this patch the dumping process doesn't have SIGNAL_GROUP_EXIT, we set
signal->group_exit_task instead. This makes signal_group_exit() true and
thus this should equally close the races with exit/exec/stop but allows to
kill the dumping thread reliably.
Notes:
- It is not clear what should we do with ->group_exit_code
if the dumper was killed, see the next change.
- we need more (hopefully straightforward) changes to ensure
that SIGKILL actually interrupts the coredump. Basically we
need to check __fatal_signal_pending() in dump_write() and
dump_seek().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Neil Horman <nhorman@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Roland McGrath <roland@hack.frob.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are 2 well known and ancient problems with coredump/signals, and a
lot of related bug reports:
- do_coredump() clears TIF_SIGPENDING but of course this can't help
if, say, SIGCHLD comes after that.
In this case the coredump can fail unexpectedly. See for example
wait_for_dump_helper()->signal_pending() check but there are other
reasons.
- At the same time, dumping a huge core on the slow media can take a
lot of time/resources and there is no way to kill the coredumping
task reliably. In particular this is not oom_kill-friendly.
This patch tries to fix the 1st problem, and makes the preparation for the
next changes.
We add the new SIGNAL_GROUP_COREDUMP flag set by zap_threads() to indicate
that this process dumps the core. prepare_signal() checks this flag and
nacks any signal except SIGKILL.
Note that this check tries to be conservative, in the long term we should
probably treat the SIGNAL_GROUP_EXIT case equally but this needs more
discussion. See marc.info/?l=linux-kernel&m=120508897917439
Notes:
- recalc_sigpending() doesn't check SIGNAL_GROUP_COREDUMP.
The patch assumes that dump_write/etc paths should never
call it, but we can change it as well.
- There is another source of TIF_SIGPENDING, freezer. This
will be addressed separately.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Neil Horman <nhorman@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Roland McGrath <roland@hack.frob.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This function suffers from not being able to determine if the cleanup is
called in case it returns -ENOMEM. Nobody is using it anymore, so let's
remove it.
Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Tejun Heo <tj@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
