linux/kernel/sched.c, branch v2.6.38

SUNRPC: Close a race in __rpc_wait_for_completion_task()

2011-03-10T20:04:52Z

Although they run as rpciod background tasks, under normal operation (i.e. no SIGKILL), functions like nfs_sillyrename(), nfs4_proc_unlck() and nfs4_do_close() want to be fully synchronous. This means that when we exit, we want all references to the rpc_task to be gone, and we want any dentry references etc. held by that task to be released. For this reason these functions call __rpc_wait_for_completion_task(), followed by rpc_put_task() in the expectation that the latter will be releasing the last reference to the rpc_task, and thus ensuring that the callback_ops->rpc_release() has been called synchronously. This patch fixes a race which exists due to the fact that rpciod calls rpc_complete_task() (in order to wake up the callers of __rpc_wait_for_completion_task()) and then subsequently calls rpc_put_task() without ensuring that these two steps are done atomically. In order to avoid adding new spin locks, the patch uses the existing waitqueue spin lock to order the rpc_task reference count releases between the waiting process and rpciod. The common case where nobody is waiting for completion is optimised for by checking if the RPC_TASK_ASYNC flag is cleared and/or if the rpc_task reference count is 1: in those cases we drop trying to grab the spin lock, and immediately free up the rpc_task. Those few processes that need to put the rpc_task from inside an asynchronous context and that do not care about ordering are given a new helper: rpc_put_task_async(). Signed-off-by: Trond Myklebust

Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2011-01-21T00:37:55Z

* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: sched, cgroup: Use exit hook to avoid use-after-free crash sched: Fix signed unsigned comparison in check_preempt_tick() sched: Replace rq->bkl_count with rq->rq_sched_info.bkl_count sched, autogroup: Fix CONFIG_RT_GROUP_SCHED sched_setscheduler() failure sched: Display autogroup names in /proc/sched_debug sched: Reinstate group names in /proc/sched_debug sched: Update effective_load() to use global share weights

sched, cgroup: Use exit hook to avoid use-after-free crash

2011-01-19T11:51:32Z

By not notifying the controller of the on-exit move back to init_css_set, we fail to move the task out of the previous cgroup's cfs_rq. This leads to an opportunity for a cgroup-destroy to come in and free the cgroup (there are no active tasks left in it after all) to which the not-quite dead task is still enqueued. Reported-by: Miklos Vajna Fixed-by: Mike Galbraith Signed-off-by: Peter Zijlstra Cc: Cc: Mike Galbraith Signed-off-by: Ingo Molnar LKML-Reference: <1293206353.29444.205.camel@laptop>

sched: Replace rq->bkl_count with rq->rq_sched_info.bkl_count

2011-01-18T14:09:43Z

Now rq->rq_sched_info.bkl_count is not used for rq, scroll rq->bkl_count into it. Thus we can save some space for rq. Signed-off-by: Yong Zhang Signed-off-by: Peter Zijlstra LKML-Reference: <1294991859-13246-1-git-send-email-yong.zhang0@gmail.com> Signed-off-by: Ingo Molnar

sched, autogroup: Fix CONFIG_RT_GROUP_SCHED sched_setscheduler() failure

2011-01-18T14:09:42Z

If CONFIG_RT_GROUP_SCHED is set, __sched_setscheduler() fails due to autogroup not allocating rt_runtime. Free unused/unusable rt_se and rt_rq, redirect RT tasks to the root task group, and tell __sched_setscheduler() that it's ok. Reported-and-tested-by: Bharata B Rao Signed-off-by: Mike Galbraith Signed-off-by: Peter Zijlstra LKML-Reference: <1294890890.8089.39.camel@marge.simson.net> Signed-off-by: Ingo Molnar

Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial

2011-01-13T18:05:56Z

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (43 commits) Documentation/trace/events.txt: Remove obsolete sched_signal_send. writeback: fix global_dirty_limits comment runtime -> real-time ppc: fix comment typo singal -> signal drivers: fix comment typo diable -> disable. m68k: fix comment typo diable -> disable. wireless: comment typo fix diable -> disable. media: comment typo fix diable -> disable. remove doc for obsolete dynamic-printk kernel-parameter remove extraneous 'is' from Documentation/iostats.txt Fix spelling milisec -> ms in snd_ps3 module parameter description Fix spelling mistakes in comments Revert conflicting V4L changes i7core_edac: fix typos in comments mm/rmap.c: fix comment sound, ca0106: Fix assignment to 'channel'. hrtimer: fix a typo in comment init/Kconfig: fix typo anon_inodes: fix wrong function name in comment fix comment typos concerning "consistent" poll: fix a typo in comment ... Fix up trivial conflicts in: - drivers/net/wireless/iwlwifi/iwl-core.c (moved to iwl-legacy.c) - fs/ext4/ext4.h Also fix missed 'diabled' typo in drivers/net/bnx2x/bnx2x.h while at it.

sched: Fix strncmp operation

2011-01-07T14:55:10Z

One of the operands, buf, is incorrect, since it is stripped and the correct address for subsequent string comparing could change if leading white spaces, if any, are removed from buf. It is fixed by replacing buf with cmp. Signed-off-by: Hillf Danton Signed-off-by: Peter Zijlstra LKML-Reference: Signed-off-by: Ingo Molnar

sched: Fix struct autogroup memory leak

2011-01-07T14:54:37Z

Seems I lost a change somewhere, leaking memory. sched: fix struct autogroup memory leak Add missing change to actually use autogroup_free(). Signed-off-by: Mike Galbraith Signed-off-by: Peter Zijlstra LKML-Reference: <1294222285.8369.2.camel@marge.simson.net> Signed-off-by: Ingo Molnar

sched: Consolidate the name of root_task_group and init_task_group

2011-01-07T14:54:34Z

root_task_group is the leftover of USER_SCHED, now it's always same to init_task_group. But as Mike suggested, root_task_group is maybe the suitable name to keep for a tree. So in this patch: init_task_group --> root_task_group init_task_group_load --> root_task_group_load INIT_TASK_GROUP_LOAD --> ROOT_TASK_GROUP_LOAD Suggested-by: Mike Galbraith Signed-off-by: Yong Zhang Signed-off-by: Peter Zijlstra LKML-Reference: <20110107071736.GA32635@windriver.com> Signed-off-by: Ingo Molnar

Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2011-01-06T18:23:33Z

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (30 commits) sched: Change wait_for_completion_*_timeout() to return a signed long sched, autogroup: Fix reference leak sched, autogroup: Fix potential access to freed memory sched: Remove redundant CONFIG_CGROUP_SCHED ifdef sched: Fix interactivity bug by charging unaccounted run-time on entity re-weight sched: Move periodic share updates to entity_tick() printk: Use this_cpu_{read|write} api on printk_pending sched: Make pushable_tasks CONFIG_SMP dependant sched: Add 'autogroup' scheduling feature: automated per session task groups sched: Fix unregister_fair_sched_group() sched: Remove unused argument dest_cpu to migrate_task() mutexes, sched: Introduce arch_mutex_cpu_relax() sched: Add some clock info to sched_debug cpu: Remove incorrect BUG_ON cpu: Remove unused variable sched: Fix UP build breakage sched: Make task dump print all 15 chars of proc comm sched: Update tg->shares after cpu.shares write sched: Allow update_cfs_load() to update global load sched: Implement demand based update_cfs_load() ...