This project is mirrored from https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git.
Pull mirroring updated .
- Feb 08, 2008
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Oleg Nesterov authored
sys_setsid() still deals with pid_t's from the global namespace. This means that the "session > 1" check can't help for sub-namespace init, setsid() can't succeed because copy_process(CLONE_NEWPID) populates PIDTYPE_PGID/SID links. Remove the usage of task_struct->pid and convert the code to use "struct pid". This also simplifies and speedups the code, saves one find_pid(). Signed-off-by:
Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by:
Pavel Emelyanov <xemul@openvz.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Oleg Nesterov authored
sys_setpgid() does unneeded conversions from pid_t to "struct pid" and vice versa. Use "struct pid" more consistently. Saves one find_vpid() and eliminates the explicit usage of ->nsproxy->pid_ns. Imho, cleanups the code. Also use the same_thread_group() helper. Signed-off-by:
"Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by:
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- Feb 06, 2008
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Eric Dumazet authored
groups_sort() can be quite long if user loads a large gid table. This is because GROUP_AT(group_info, some_integer) uses an integer divide. So having to do XXX thousand divides during one syscall can lead to very high latencies. (NGROUPS_MAX=65536) In the past (25 Mar 2006), an analog problem was found in groups_search() (commit d74beb9f ) and at that time I changed some variables to unsigned int. I believe that a more generic fix is to make sure NGROUPS_PER_BLOCK is unsigned. Signed-off-by:
Eric Dumazet <dada1@cosmosbay.com> Signed-off-by:
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Eric Dumazet authored
NR_OPEN (historically set to 1024*1024) actually forbids processes to open more than 1024*1024 handles. Unfortunatly some production servers hit the not so 'ridiculously high value' of 1024*1024 file descriptors per process. Changing NR_OPEN is not considered safe because of vmalloc space potential exhaust. This patch introduces a new sysctl (/proc/sys/fs/nr_open) wich defaults to 1024*1024, so that admins can decide to change this limit if their workload needs it. [akpm@linux-foundation.org: export it for sparc64] Signed-off-by:
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- Feb 05, 2008
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Adrian Bunk authored
kernel_shutdown_prepare() can now become static. Signed-off-by:
Adrian Bunk <bunk@kernel.org> Acked-by:
Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by:
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Serge E. Hallyn authored
The capability bounding set is a set beyond which capabilities cannot grow. Currently cap_bset is per-system. It can be manipulated through sysctl, but only init can add capabilities. Root can remove capabilities. By default it includes all caps except CAP_SETPCAP. This patch makes the bounding set per-process when file capabilities are enabled. It is inherited at fork from parent. Noone can add elements, CAP_SETPCAP is required to remove them. One example use of this is to start a safer container. For instance, until device namespaces or per-container device whitelists are introduced, it is best to take CAP_MKNOD away from a container. The bounding set will not affect pP and pE immediately. It will only affect pP' and pE' after subsequent exec()s. It also does not affect pI, and exec() does not constrain pI'. So to really start a shell with no way of regain CAP_MKNOD, you would do prctl(PR_CAPBSET_DROP, CAP_MKNOD); cap_t cap = cap_get_proc(); cap_value_t caparray[1]; caparray[0] = CAP_MKNOD; cap_set_flag(cap, CAP_INHERITABLE, 1, caparray, CAP_DROP); cap_set_proc(cap); cap_free(cap); The following test program will get and set the bounding set (but not pI). For instance ./bset get (lists capabilities in bset) ./bset drop cap_net_raw (starts shell with new bset) (use capset, setuid binary, or binary with file capabilities to try to increase caps) ************************************************************ cap_bound.c ************************************************************ #include <sys/prctl.h> #include <linux/capability.h> #include <sys/types.h> #include <unistd.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #ifndef PR_CAPBSET_READ #define PR_CAPBSET_READ 23 #endif #ifndef PR_CAPBSET_DROP #define PR_CAPBSET_DROP 24 #endif int usage(char *me) { printf("Usage: %s get\n", me); printf(" %s drop <capability>\n", me); return 1; } #define numcaps 32 char *captable[numcaps] = { "cap_chown", "cap_dac_override", "cap_dac_read_search", "cap_fowner", "cap_fsetid", "cap_kill", "cap_setgid", "cap_setuid", "cap_setpcap", "cap_linux_immutable", "cap_net_bind_service", "cap_net_broadcast", "cap_net_admin", "cap_net_raw", "cap_ipc_lock", "cap_ipc_owner", "cap_sys_module", "cap_sys_rawio", "cap_sys_chroot", "cap_sys_ptrace", "cap_sys_pacct", "cap_sys_admin", "cap_sys_boot", "cap_sys_nice", "cap_sys_resource", "cap_sys_time", "cap_sys_tty_config", "cap_mknod", "cap_lease", "cap_audit_write", "cap_audit_control", "cap_setfcap" }; int getbcap(void) { int comma=0; unsigned long i; int ret; printf("i know of %d capabilities\n", numcaps); printf("capability bounding set:"); for (i=0; i<numcaps; i++) { ret = prctl(PR_CAPBSET_READ, i); if (ret < 0) perror("prctl"); else if (ret==1) printf("%s%s", (comma++) ? ", " : " ", captable[i]); } printf("\n"); return 0; } int capdrop(char *str) { unsigned long i; int found=0; for (i=0; i<numcaps; i++) { if (strcmp(captable[i], str) == 0) { found=1; break; } } if (!found) return 1; if (prctl(PR_CAPBSET_DROP, i)) { perror("prctl"); return 1; } return 0; } int main(int argc, char *argv[]) { if (argc<2) return usage(argv[0]); if (strcmp(argv[1], "get")==0) return getbcap(); if (strcmp(argv[1], "drop")!=0 || argc<3) return usage(argv[0]); if (capdrop(argv[2])) { printf("unknown capability\n"); return 1; } return execl("/bin/bash", "/bin/bash", NULL); } ************************************************************ [serue@us.ibm.com: fix typo] Signed-off-by:Serge E. Hallyn <serue@us.ibm.com> Signed-off-by:
Andrew G. Morgan <morgan@kernel.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: James Morris <jmorris@namei.org> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Casey Schaufler <casey@schaufler-ca.com>a Signed-off-by:
Jiri Slaby <jirislaby@gmail.com> Signed-off-by:
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- Nov 17, 2007
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Ingo Molnar authored
dont use the vgetcpu tcache - it's causing problems with tasks migrating, they'll see the old cache up to a jiffy after the migration, further increasing the costs of the migration. In the worst case they see a complete bogus information from the tcache, when a sys_getcpu() call "invalidated" the cache info by incrementing the jiffies _and_ the cpuid info in the cache and the following vdso_getcpu() call happens after vdso_jiffies have been incremented. Signed-off-by:
Ingo Molnar <mingo@elte.hu> Signed-off-by:
Ulrich Drepper <drepper@redhat.com> Signed-off-by:
Thomas Gleixner <tglx@linutronix.de>
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- Oct 19, 2007
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Pavel Emelyanov authored
The pgrp field is not used widely around the kernel so it is now marked as deprecated with appropriate comment. The initialization of INIT_SIGNALS is trimmed because a) they are set to 0 automatically; b) gcc cannot properly initialize two anonymous (the second one is the one with the session) unions. In this particular case to make it compile we'd have to add some field initialized right before the .pgrp. This is the same patch as the 1ec320af one (from Cedric), but for the pgrp field. Some progress report: We have to deprecate the pid, tgid, session and pgrp fields on struct task_struct and struct signal_struct. The session and pgrp are already deprecated. The tgid value is close to being such - the worst known usage in in fs/locks.c and audit code. The pid field deprecation is mainly blocked by numerous printk-s around the kernel that print the tsk->pid to log. Signed-off-by:
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Pavel Emelyanov authored
The find_task_by_something is a set of macros are used to find task by pid depending on what kind of pid is proposed - global or virtual one. All of them are wrappers above the most generic one - find_task_by_pid_type_ns() - and just substitute some args for it. It turned out, that dereferencing the current->nsproxy->pid_ns construction and pushing one more argument on the stack inline cause kernel text size to grow. This patch moves all this stuff out-of-line into kernel/pid.c. Together with the next patch it saves a bit less than 400 bytes from the .text section. Signed-off-by:
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Pavel Emelyanov authored
This is the largest patch in the set. Make all (I hope) the places where the pid is shown to or get from user operate on the virtual pids. The idea is: - all in-kernel data structures must store either struct pid itself or the pid's global nr, obtained with pid_nr() call; - when seeking the task from kernel code with the stored id one should use find_task_by_pid() call that works with global pids; - when showing pid's numerical value to the user the virtual one should be used, but however when one shows task's pid outside this task's namespace the global one is to be used; - when getting the pid from userspace one need to consider this as the virtual one and use appropriate task/pid-searching functions. [akpm@linux-foundation.org: build fix] [akpm@linux-foundation.org: nuther build fix] [akpm@linux-foundation.org: yet nuther build fix] [akpm@linux-foundation.org: remove unneeded casts] Signed-off-by:
Alexey Dobriyan <adobriyan@openvz.org> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Paul Menage <menage@google.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by:
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Pavel Emelianov authored
The set of functions process_session, task_session, process_group and task_pgrp is confusing, as the names can be mixed with each other when looking at the code for a long time. The proposals are to * equip the functions that return the integer with _nr suffix to represent that fact, * and to make all functions work with task (not process) by making the common prefix of the same name. For monotony the routines signal_session() and set_signal_session() are replaced with task_session_nr() and set_task_session(), especially since they are only used with the explicit task->signal dereference. Signed-off-by:
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Alexey Dobriyan authored
There is separate notifier header, but no separate notifier .c file. Extract notifier code out of kernel/sys.c which will remain for misc syscalls I hope. Merge kernel/die_notifier.c into kernel/notifier.c. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by:
Alexey Dobriyan <adobriyan@sw.ru> Signed-off-by:
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- Oct 18, 2007
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Adrian Bunk authored
This patch removes the unused EXPORT_SYMBOL(pm_power_off_prepare). Signed-off-by:
Adrian Bunk <bunk@stusta.de> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by:
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- Oct 01, 2007
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Mark Lord authored
We need to disable all CPUs other than the boot CPU (usually 0) before attempting to power-off modern SMP machines. This fixes the hang-on-poweroff issue on my MythTV SMP box, and also on Thomas Gleixner's new toybox. Signed-off-by:
Mark Lord <mlord@pobox.com> Acked-by:
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- Aug 31, 2007
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Oleg Nesterov authored
Spotted by Marcin Kowalczyk <qrczak@knm.org.pl>. sys_setpgid(child) fails if the child was forked by sub-thread. Fix the "is it our child" check. The previous commit ee0acf90 was not complete. (this patch asks for the new same_thread_group() helper, but mainline doesn't have it yet). Signed-off-by:
Roland McGrath <roland@redhat.com> Cc: <stable@kernel.org> Tested-by:
"Marcin 'Qrczak' Kowalczyk" <qrczak@knm.org.pl> Signed-off-by:
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- Jul 29, 2007
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Rafael J. Wysocki authored
Replace CONFIG_SOFTWARE_SUSPEND with CONFIG_HIBERNATION to avoid confusion (among other things, with CONFIG_SUSPEND introduced in the next patch). Signed-off-by:
Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by:
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- Jul 26, 2007
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Rafael J. Wysocki authored
Commit bd804eba ("PM: Introduce pm_power_off_prepare") caused problems in the poweroff path, as reported by YOSHIFUJI Hideaki / 吉藤英明. Generally, sysdev_shutdown() should be called after the ACPI preparation for powering the system off. To make it happen, we can separate sysdev_shutdown() from device_shutdown() and call it directly wherever necessary. Signed-off-by:
YOSHIFUJI Hideaki / 吉藤英明 <yoshfuji@linux-ipv6.org> Signed-off-by:
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- Jul 19, 2007
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Kawai, Hidehiro authored
This patch changes mm_struct.dumpable to a pair of bit flags. set_dumpable() converts three-value dumpable to two flags and stores it into lower two bits of mm_struct.flags instead of mm_struct.dumpable. get_dumpable() behaves in the opposite way. [akpm@linux-foundation.org: export set_dumpable] Signed-off-by:
Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: David Howells <dhowells@redhat.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by:
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Rafael J. Wysocki authored
Introduce the pm_power_off_prepare() callback that can be registered by the interested platforms in analogy with pm_idle() and pm_power_off(), used for preparing the system to power off (needed by ACPI). This allows us to drop acpi_sysclass and device_acpi that are only defined in order to register the ACPI power off preparation callback, which is needed by pm_power_off() registered in a much different way. Signed-off-by:
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- Jul 18, 2007
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Jeremy Fitzhardinge authored
Rather than using a tri-state integer for the wait flag in call_usermodehelper_exec, define a proper enum, and use that. I've preserved the integer values so that any callers I've missed should still work OK. Signed-off-by:Jeremy Fitzhardinge <jeremy@xensource.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Andi Kleen <ak@suse.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Bjorn Helgaas <bjorn.helgaas@hp.com> Cc: Joel Becker <joel.becker@oracle.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: David Howells <dhowells@redhat.com>
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Jeremy Fitzhardinge authored
Various pieces of code around the kernel want to be able to trigger an orderly poweroff. This pulls them together into a single implementation. By default the poweroff command is /sbin/poweroff, but it can be set via sysctl: kernel/poweroff_cmd. This is split at whitespace, so it can include command-line arguments. This patch replaces four other instances of invoking either "poweroff" or "shutdown -h now": two sbus drivers, and acpi thermal management. sparc64 has its own "powerd"; still need to determine whether it should be replaced by orderly_poweroff(). Signed-off-by:
Len Brown <lenb@kernel.org> Signed-off-by:
Chris Wright <chrisw@sous-sol.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Andi Kleen <ak@suse.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: David S. Miller <davem@davemloft.net>
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- Jul 16, 2007
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Andrea Arcangeli authored
This reduces the memory footprint and it enforces that only the current task can enable seccomp on itself (this is a requirement for a strightforward [modulo preempt ;) ] TIF_NOTSC implementation). Signed-off-by:
Andrea Arcangeli <andrea@cpushare.com> Signed-off-by:
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Cedric Le Goater authored
Basically, it will allow a process to unshare its user_struct table, resetting at the same time its own user_struct and all the associated accounting. A new root user (uid == 0) is added to the user namespace upon creation. Such root users have full privileges and it seems that theses privileges should be controlled through some means (process capabilities ?) The unshare is not included in this patch. Changes since [try #4]: - Updated get_user_ns and put_user_ns to accept NULL, and get_user_ns to return the namespace. Changes since [try #3]: - moved struct user_namespace to files user_namespace.{c,h} Changes since [try #2]: - removed struct user_namespace* argument from find_user() Changes since [try #1]: - removed struct user_namespace* argument from find_user() - added a root_user per user namespace Signed-off-by:Cedric Le Goater <clg@fr.ibm.com> Signed-off-by:
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- May 11, 2007
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Sukadev Bhattiprolu authored
attach_pid() currently takes a pid_t and then uses find_pid() to find the corresponding struct pid. Sometimes we already have the struct pid. We can then skip find_pid() if attach_pid() were to take a struct pid parameter. Signed-off-by:
Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: <containers@lists.osdl.org> Signed-off-by:
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Daniel Walker authored
Switch to the defines for these two checks, instead of hard coding the values. [akpm@linux-foundation.org: add missing include] Signed-off-by:
Daniel Walker <dwalker@mvista.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by:
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Eric Dumazet authored
If CONFIG_TASK_IO_ACCOUNTING is defined, we update io accounting counters for each task. This patch permits reporting of values using the well known getrusage() syscall, filling ru_inblock and ru_oublock instead of null values. As TASK_IO_ACCOUNTING currently counts bytes counts, we approximate blocks count doing : nr_blocks = nr_bytes / 512 Example of use : ---------------------- After patch is applied, /usr/bin/time command can now give a good approximation of IO that the process had to do. $ /usr/bin/time grep tototo /usr/include/* Command exited with non-zero status 1 0.00user 0.02system 0:02.11elapsed 1%CPU (0avgtext+0avgdata 0maxresident)k 24288inputs+0outputs (0major+259minor)pagefaults 0swaps $ /usr/bin/time dd if=/dev/zero of=/tmp/testfile count=1000 1000+0 enregistrements lus 1000+0 enregistrements écrits 512000 octets (512 kB) copiés, 0,00326601 seconde, 157 MB/s 0.00user 0.00system 0:00.00elapsed 80%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+3000outputs (0major+299minor)pagefaults 0swaps Signed-off-by:
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- May 09, 2007
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Gautham R Shenoy authored
Since 2.6.18-something, the community has been bugged by the problem to provide a clean and a stable mechanism to postpone a cpu-hotplug event as lock_cpu_hotplug was badly broken. This is another proposal towards solving that problem. This one is along the lines of the solution provided in kernel/workqueue.c Instead of having a global mechanism like lock_cpu_hotplug, we allow the subsytems to define their own per-subsystem hot cpu mutexes. These would be taken(released) where ever we are currently calling lock_cpu_hotplug(unlock_cpu_hotplug). Also, in the per-subsystem hotcpu callback function,we take this mutex before we handle any pre-cpu-hotplug events and release it once we finish handling the post-cpu-hotplug events. A standard means for doing this has been provided in [PATCH 2/4] and demonstrated in [PATCH 3/4]. The ordering of these per-subsystem mutexes might still prove to be a problem, but hopefully lockdep should help us get out of that muddle. The patch set to be applied against linux-2.6.19-rc5 is as follows: [PATCH 1/4] : Extend notifier_call_chain with an option to specify the number of notifications to be sent and also count the number of notifications actually sent. [PATCH 2/4] : Define events CPU_LOCK_ACQUIRE and CPU_LOCK_RELEASE and send out notifications for these in _cpu_up and _cpu_down. This would help us standardise the acquire and release of the subsystem locks in the hotcpu callback functions of these subsystems. [PATCH 3/4] : Eliminate lock_cpu_hotplug from kernel/sched.c. [PATCH 4/4] : In workqueue_cpu_callback function, acquire(release) the workqueue_mutex while handling CPU_LOCK_ACQUIRE(CPU_LOCK_RELEASE). If the per-subsystem-locking approach survives the test of time, we can expect a slow phasing out of lock_cpu_hotplug, which has not yet been eliminated in these patches :) This patch: Provide notifier_call_chain with an option to call only a specified number of notifiers and also record the number of call to notifiers made. The need for this enhancement was identified in the post entitled "Slab - Eliminate lock_cpu_hotplug from slab" (http://lkml.org/lkml/2006/10/28/92 ) by Ravikiran G Thirumalai and Andrew Morton. This patch adds two additional parameters to notifier_call_chain API namely - int nr_to_calls : Number of notifier_functions to be called. The don't care value is -1. - unsigned int *nr_calls : Records the total number of notifier_funtions called by notifier_call_chain. The don't care value is NULL. [michal.k.k.piotrowski@gmail.com: build fix] Credit: Andrew Morton <akpm@osdl.org> Signed-off-by:
Gautham R Shenoy <ego@in.ibm.com> Signed-off-by:
Michal Piotrowski <michal.k.k.piotrowski@gmail.com> Signed-off-by:
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Rafael J. Wysocki authored
[ With Johannes Berg <johannes@sipsolutions.net> ] Separate the hibernation (aka suspend to disk code) from the other suspend code. In particular: * Remove the definitions related to hibernation from include/linux/pm.h * Introduce struct hibernation_ops and a new hibernate() function to hibernate the system, defined in include/linux/suspend.h * Separate suspend code in kernel/power/main.c from hibernation-related code in kernel/power/disk.c and kernel/power/user.c (with the help of hibernation_ops) * Switch ACPI (the only user of pm_ops.pm_disk_mode) to hibernation_ops Signed-off-by:
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John Anthony Kazos Jr authored
Convert the "kernel" subdirectory of the tree to UTF-8. The only file modified is <kernel/sys.c>. Signed-off-by:
John Anthony Kazos Jr. <jakj@j-a-k-j.com> Signed-off-by:
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- May 08, 2007
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Tom Alsberg authored
As discovered here today, the change in Kernel 2.6.17 intended to inhibit users from setting RLIMIT_CPU to 0 (as that is equivalent to unlimited) by "cheating" and setting it to 1 in such a case, does not make a difference, as the check is done in the wrong place (too late), and only applies to the profiling code. On all systems I checked running kernels above 2.6.17, no matter what the hard and soft CPU time limits were before, a user could escape them by issuing in the shell (sh/bash/zsh) "ulimit -t 0", and then the user's process was not ever killed. Attached is a trivial patch to fix that. Simply moving the check to a slightly earlier location (specifically, before the line that actually assigns the limit - *old_rlim = new_rlim), does the trick. Do note that at least the zsh (but not ash, dash, or bash) shell has the problem of "caching" the limits set by the ulimit command, so when running zsh the fix will not immediately be evident - after entering "ulimit -t 0", "ulimit -a" will show "-t: cpu time (seconds) 0", even though the actual limit as returned by getrlimit(...) will be 1. It can be verified by opening a subshell (which will not have the values of the parent shell in cache) and checking in it, or just by running a CPU intensive command like "echo '65536^1048576' | bc" and verifying that it dumps core after one second. Regardless of whether that is a misfeature in the shell, perhaps it would be better to return -EINVAL from setrlimit in such a case instead of cheating and setting to 1, as that does not really reflect the actual state of the process anymore. I do not however know what the ground for that decision was in the original 2.6.17 change, and whether there would be any "backward" compatibility issues, so I preferred not to touch that right now. Signed-off-by:
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- May 07, 2007
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Johannes Berg authored
Remove software_suspend() and all its users since pm_suspend(PM_SUSPEND_DISK) should be equivalent and there's no point in having two interfaces for the same thing. The patch also changes the valid_state function to return 0 (false) for PM_SUSPEND_DISK when SOFTWARE_SUSPEND is not configured instead of accepting it and having the whole thing fail later. Signed-off-by:
Johannes Berg <johannes@sipsolutions.net> Acked-by:
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- Feb 12, 2007
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Eric W. Biederman authored
There isn't any real advantage to this change except that it allows the old functions to be removed. Which is easier on maintenance and puts the code in a more uniform style. Signed-off-by:
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Eric W. Biederman authored
Of kernel subsystems that work with pids the tty layer is probably the largest consumer. But it has the nice virtue that the assiation with a session only lasts until the session leader exits. Which means that no reference counting is required. So using struct pid winds up being a simple optimization to avoid hash table lookups. In the long term the use of pid_nr also ensures that when we have multiple pid spaces mixed everything will work correctly. Signed-off-by:
Eric W. Biederman <eric@maxwell.lnxi.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by:
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- Feb 11, 2007
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Robert P. J. Day authored
A variety of (mostly) innocuous fixes to the embedded kernel-doc content in source files, including: * make multi-line initial descriptions single line * denote some function names, constants and structs as such * change erroneous opening '/*' to '/**' in a few places * reword some text for clarity Signed-off-by:
Robert P. J. Day <rpjday@mindspring.com> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Signed-off-by:
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- Jan 23, 2007
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Ingo Molnar authored
while lock-profiling the -rt kernel i noticed weird contention during mmap-intense workloads, and the tracer showed the following gem, in one of our MM hotpaths: threaded-2771 1.... 65us : sys_munmap (sysenter_do_call) threaded-2771 1.... 66us : profile_munmap (sys_munmap) threaded-2771 1.... 66us : blocking_notifier_call_chain (profile_munmap) threaded-2771 1.... 66us : rt_down_read (blocking_notifier_call_chain) ouch! a global rw-semaphore taken in one of the most performance- sensitive codepaths of the kernel. And i dont even have oprofile enabled! All distro kernels have CONFIG_PROFILING enabled, so this scalability problem affects the majority of Linux users. The fix is to enhance blocking_notifier_call_chain() to only take the lock if there appears to be work on the call-chain. With this patch applied i get nicely saturated system, and much higher munmap performance, on SMP systems. And as a bonus this also fixes a similar scalability bottleneck in the thread-exit codepath: profile_task_exit() ... Signed-off-by:
Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by:
Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by:
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- Dec 08, 2006
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Oleg Nesterov authored
All tasks in the process group have the same sid, we don't need to iterate them all to check that the caller of sys_setpgid() doesn't change its session. Signed-off-by:
Andrew Morton <akpm@osdl.org> Signed-off-by:
Linus Torvalds <torvalds@osdl.org>
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Cedric Le Goater authored
Replace occurences of task->signal->session by a new process_session() helper routine. It will be useful for pid namespaces to abstract the session pid number. Signed-off-by:
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Peter Zijlstra authored
Fix the locking of signal->tty. Use ->sighand->siglock to protect ->signal->tty; this lock is already used by most other members of ->signal/->sighand. And unless we are 'current' or the tasklist_lock is held we need ->siglock to access ->signal anyway. (NOTE: sys_unshare() is broken wrt ->sighand locking rules) Note that tty_mutex is held over tty destruction, so while holding tty_mutex any tty pointer remains valid. Otherwise the lifetime of ttys are governed by their open file handles. This leaves some holes for tty access from signal->tty (or any other non file related tty access). It solves the tty SLAB scribbles we were seeing. (NOTE: the change from group_send_sig_info to __group_send_sig_info needs to be examined by someone familiar with the security framework, I think it is safe given the SEND_SIG_PRIV from other __group_send_sig_info invocations) [schwidefsky@de.ibm.com: 3270 fix] [akpm@osdl.org: various post-viro fixes] Signed-off-by:Alan Cox <alan@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Roland McGrath <roland@redhat.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: James Morris <jmorris@namei.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jan Kara <jack@ucw.cz> Signed-off-by:
Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by:
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- Dec 07, 2006
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David Rientjes authored
Remove unused 'new_ruid' variable. Reported by David Binderman <dcb314@hotmail.com>. Signed-off-by:
David Rientjes <rientjes@cs.washington.edu> Signed-off-by:
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- Nov 22, 2006
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David Howells authored
Pass the work_struct pointer to the work function rather than context data. The work function can use container_of() to work out the data. For the cases where the container of the work_struct may go away the moment the pending bit is cleared, it is made possible to defer the release of the structure by deferring the clearing of the pending bit. To make this work, an extra flag is introduced into the management side of the work_struct. This governs auto-release of the structure upon execution. Ordinarily, the work queue executor would release the work_struct for further scheduling or deallocation by clearing the pending bit prior to jumping to the work function. This means that, unless the driver makes some guarantee itself that the work_struct won't go away, the work function may not access anything else in the work_struct or its container lest they be deallocated.. This is a problem if the auxiliary data is taken away (as done by the last patch). However, if the pending bit is *not* cleared before jumping to the work function, then the work function *may* access the work_struct and its container with no problems. But then the work function must itself release the work_struct by calling work_release(). In most cases, automatic release is fine, so this is the default. Special initiators exist for the non-auto-release case (ending in _NAR). Signed-Off-By:David Howells <dhowells@redhat.com>
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