user/sven/linux.git/kernel/cgroup.c, branch v3.4.110

move d_rcu from overlapping d_child to overlapping d_alias

2015-04-14T09:33:58Z

commit 946e51f2bf37f1656916eb75bd0742ba33983c28 upstream. Signed-off-by: Al Viro [bwh: Backported to 3.2: - Apply name changes in all the different places we use d_alias and d_child - Move the WARN_ON() in __d_free() to d_free() as we don't have dentry_free()] Signed-off-by: Ben Hutchings [lizf: Backported to 3.4: - adjust context - need one more name change in debugfs]

cgroup: reject cgroup names with ' '

2014-12-01T10:02:23Z

commit 71b1fb5c4473a5b1e601d41b109bdfe001ec82e0 upstream. /proc//cgroup contains one cgroup path on each line. If cgroup names are allowed to contain "\n", applications cannot parse /proc//cgroup safely. Signed-off-by: Alban Crequy Signed-off-by: Tejun Heo [lizf: Backported to 3.4: - adjust context - s/name/dentry->d_name.name/] Signed-off-by: Zefan Li

cgroup: cgroup_subsys->fork() should be called after the task is added to css_set

2014-03-11T23:10:03Z

commit 5edee61edeaaebafe584f8fb7074c1ef4658596b upstream. cgroup core has a bug which violates a basic rule about event notifications - when a new entity needs to be added, you add that to the notification list first and then make the new entity conform to the current state. If done in the reverse order, an event happening inbetween will be lost. cgroup_subsys->fork() is invoked way before the new task is added to the css_set. Currently, cgroup_freezer is the only user of ->fork() and uses it to make new tasks conform to the current state of the freezer. If FROZEN state is requested while fork is in progress between cgroup_fork_callbacks() and cgroup_post_fork(), the child could escape freezing - the cgroup isn't frozen when ->fork() is called and the freezer couldn't see the new task on the css_set. This patch moves cgroup_subsys->fork() invocation to cgroup_post_fork() after the new task is added to the css_set. cgroup_fork_callbacks() is removed. Because now a task may be migrated during cgroup_subsys->fork(), freezer_fork() is updated so that it adheres to the usual RCU locking and the rather pointless comment on why locking can be different there is removed (if it doesn't make anything simpler, why even bother?). Signed-off-by: Tejun Heo Cc: Oleg Nesterov Cc: Rafael J. Wysocki [hq: Backported to 3.4: - Adjust context - Iterate over first CGROUP_BUILTIN_SUBSYS_COUNT elements of subsys] Signed-off-by: Qiang Huang Signed-off-by: Greg Kroah-Hartman

cgroup: fail if monitored file and event_control are in different cgroup

2013-10-01T16:10:51Z

commit f169007b2773f285e098cb84c74aac0154d65ff7 upstream. If we pass fd of memory.usage_in_bytes of cgroup A to cgroup.event_control of cgroup B, then we won't get memory usage notification from A but B! What's worse, if A and B are in different mount hierarchy, we'll end up accessing NULL pointer! Disallow this kind of invalid usage. Signed-off-by: Li Zefan Acked-by: Kirill A. Shutemov Signed-off-by: Tejun Heo Cc: Weng Meiling Signed-off-by: Greg Kroah-Hartman

cgroup: fix an off-by-one bug which may trigger BUG_ON()

2013-05-08T02:51:56Z

commit 3ac1707a13a3da9cfc8f242a15b2fae6df2c5f88 upstream. The 3rd parameter of flex_array_prealloc() is the number of elements, not the index of the last element. The effect of the bug is, when opening cgroup.procs, a flex array will be allocated and all elements of the array is allocated with GFP_KERNEL flag, but the last one is GFP_ATOMIC, and if we fail to allocate memory for it, it'll trigger a BUG_ON(). Signed-off-by: Li Zefan Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

cgroup: fix exit() vs rmdir() race

2013-03-03T22:06:44Z

commit 71b5707e119653039e6e95213f00479668c79b75 upstream. In cgroup_exit() put_css_set_taskexit() is called without any lock, which might lead to accessing a freed cgroup: thread1 thread2 --------------------------------------------- exit() cgroup_exit() put_css_set_taskexit() atomic_dec(cgrp->count); rmdir(); /* not safe !! */ check_for_release(cgrp); rcu_read_lock() can be used to make sure the cgroup is alive. Signed-off-by: Li Zefan Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

cgroup: remove incorrect dget/dput() pair in cgroup_create_dir()

2013-01-11T17:06:58Z

commit 175431635ec09b1d1bba04979b006b99e8305a83 upstream. cgroup_create_dir() does weird dancing with dentry refcnt. On success, it gets and then puts it achieving nothing. On failure, it puts but there isn't no matching get anywhere leading to the following oops if cgroup_create_file() fails for whatever reason. ------------[ cut here ]------------ kernel BUG at /work/os/work/fs/dcache.c:552! invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC Modules linked in: CPU 2 Pid: 697, comm: mkdir Not tainted 3.7.0-rc4-work+ #3 Bochs Bochs RIP: 0010:[] [] dput+0x1dc/0x1e0 RSP: 0018:ffff88001a3ebef8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff88000e5b1ef8 RCX: 0000000000000403 RDX: 0000000000000303 RSI: 2000000000000000 RDI: ffff88000e5b1f58 RBP: ffff88001a3ebf18 R08: ffffffff82c76960 R09: 0000000000000001 R10: ffff880015022080 R11: ffd9bed70f48a041 R12: 00000000ffffffea R13: 0000000000000001 R14: ffff88000e5b1f58 R15: 00007fff57656d60 FS: 00007ff05fcb3800(0000) GS:ffff88001fd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000004046f0 CR3: 000000001315f000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process mkdir (pid: 697, threadinfo ffff88001a3ea000, task ffff880015022080) Stack: ffff88001a3ebf48 00000000ffffffea 0000000000000001 0000000000000000 ffff88001a3ebf38 ffffffff811cc889 0000000000000001 ffff88000e5b1ef8 ffff88001a3ebf68 ffffffff811d1fc9 ffff8800198d7f18 ffff880019106ef8 Call Trace: [] done_path_create+0x19/0x50 [] sys_mkdirat+0x59/0x80 [] sys_mkdir+0x19/0x20 [] system_call_fastpath+0x16/0x1b Code: 00 48 8d 90 18 01 00 00 48 89 93 c0 00 00 00 4c 89 a0 18 01 00 00 48 8b 83 a0 00 00 00 83 80 28 01 00 00 01 e8 e6 6f a0 00 eb 92 <0f> 0b 66 90 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 49 89 fe 41 RIP [] dput+0x1dc/0x1e0 RSP ---[ end trace 1277bcfd9561ddb0 ]--- Fix it by dropping the unnecessary dget/dput() pair. Signed-off-by: Tejun Heo Acked-by: Li Zefan Signed-off-by: Greg Kroah-Hartman

Revert "cgroup: Drop task_lock(parent) on cgroup_fork()"

2012-10-28T17:14:14Z

commit 9bb71308b8133d643648776243e4d5599b1c193d upstream. This reverts commit 7e381b0eb1e1a9805c37335562e8dc02e7d7848c. The commit incorrectly assumed that fork path always performed threadgroup_change_begin/end() and depended on that for synchronization against task exit and cgroup migration paths instead of explicitly grabbing task_lock(). threadgroup_change is not locked when forking a new process (as opposed to a new thread in the same process) and even if it were it wouldn't be effective as different processes use different threadgroup locks. Revert the incorrect optimization. Signed-off-by: Tejun Heo LKML-Reference: <20121008020000.GB2575@localhost> Acked-by: Li Zefan Bitterly-Acked-by: Frederic Weisbecker Signed-off-by: Greg Kroah-Hartman

Revert "cgroup: Remove task_lock() from cgroup_post_fork()"

2012-10-28T17:14:14Z

commit d87838321124061f6c935069d97f37010fa417e6 upstream. This reverts commit 7e3aa30ac8c904a706518b725c451bb486daaae9. The commit incorrectly assumed that fork path always performed threadgroup_change_begin/end() and depended on that for synchronization against task exit and cgroup migration paths instead of explicitly grabbing task_lock(). threadgroup_change is not locked when forking a new process (as opposed to a new thread in the same process) and even if it were it wouldn't be effective as different processes use different threadgroup locks. Revert the incorrect optimization. Signed-off-by: Tejun Heo LKML-Reference: <20121008020000.GB2575@localhost> Acked-by: Li Zefan Cc: Frederic Weisbecker Signed-off-by: Greg Kroah-Hartman

cgroup: notify_on_release may not be triggered in some cases

2012-10-28T17:14:14Z

commit 1f5320d5972aa50d3e8d2b227b636b370e608359 upstream. notify_on_release must be triggered when the last process in a cgroup is move to another. But if the first(and only) process in a cgroup is moved to another, notify_on_release is not triggered. # mkdir /cgroup/cpu/SRC # mkdir /cgroup/cpu/DST # # echo 1 >/cgroup/cpu/SRC/notify_on_release # echo 1 >/cgroup/cpu/DST/notify_on_release # # sleep 300 & [1] 8629 # # echo 8629 >/cgroup/cpu/SRC/tasks # echo 8629 >/cgroup/cpu/DST/tasks -> notify_on_release for /SRC must be triggered at this point, but it isn't. This is because put_css_set() is called before setting CGRP_RELEASABLE in cgroup_task_migrate(), and is a regression introduce by the commit:74a1166d(cgroups: make procs file writable), which was merged into v3.0. Acked-by: Li Zefan Cc: Ben Blum Signed-off-by: Daisuke Nishimura Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman