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| author | Tejun Heo <tj@kernel.org> | 2015-09-25 16:24:27 -0400 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2015-09-25 16:25:07 -0400 |
| commit | a3e72739b7a7ea225dd11c4096f97123f6427d87 (patch) | |
| tree | 60f7c8d79db9e09f2ac8b097928fa0e4034ba631 /kernel/cgroup.c | |
| parent | c0522908d22e0b8669e01a7706720996c773e7f4 (diff) | |
| download | linux-a3e72739b7a7ea225dd11c4096f97123f6427d87.tar.gz linux-a3e72739b7a7ea225dd11c4096f97123f6427d87.tar.bz2 linux-a3e72739b7a7ea225dd11c4096f97123f6427d87.zip | |
cgroup: fix too early usage of static_branch_disable()
49d1dc4b8179 ("cgroup: implement static_key based
cgroup_subsys_enabled() and cgroup_subsys_on_dfl()") converted cgroup
enabled test to use static_key; however, cgroup_disable() is called
before static_key subsystem itself is initialized and thus leads to
the following warning when "cgroup_disable=" parameter is specified.
WARNING: CPU: 0 PID: 0 at kernel/jump_label.c:99 static_key_slow_dec+0x44/0x60()
static_key_slow_dec used before call to jump_label_init
...
Call Trace:
[<ffffffff813b18c2>] dump_stack+0x44/0x62
[<ffffffff8108dd52>] warn_slowpath_common+0x82/0xc0
[<ffffffff8108ddec>] warn_slowpath_fmt+0x5c/0x80
[<ffffffff8119c054>] static_key_slow_dec+0x44/0x60
[<ffffffff81d826b6>] cgroup_disable+0xaf/0xd6
[<ffffffff81d5f9de>] unknown_bootoption+0x8c/0x194
[<ffffffff810b0c03>] parse_args+0x273/0x4a0
[<ffffffff81d5fd67>] start_kernel+0x205/0x4b8
...
Fix it by making cgroup_disable() to record the subsystems to disable
in cgroup_disable_mask and moving the actual application to
cgroup_init() which is late enough and where the enabled state is
first used.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Andrey Wagin <avagin@gmail.com>
Link: http://lkml.kernel.org/g/CANaxB-yFuS4SA2znSvcKrO9L_CbHciHYW+o9bN8sZJ8eR9FxYA@mail.gmail.com
Fixes: 49d1dc4b81797f88270832b11e9f73809e7e7209
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index f924158a1b65..ae23814b0c6e 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -5124,6 +5124,8 @@ int __init cgroup_init_early(void) return 0; } +static unsigned long cgroup_disable_mask __initdata; + /** * cgroup_init - cgroup initialization * @@ -5170,8 +5172,12 @@ int __init cgroup_init(void) * disabled flag and cftype registration needs kmalloc, * both of which aren't available during early_init. */ - if (!cgroup_ssid_enabled(ssid)) + if (cgroup_disable_mask & (1 << ssid)) { + static_branch_disable(cgroup_subsys_enabled_key[ssid]); + printk(KERN_INFO "Disabling %s control group subsystem\n", + ss->name); continue; + } cgrp_dfl_root.subsys_mask |= 1 << ss->id; @@ -5595,11 +5601,7 @@ static int __init cgroup_disable(char *str) if (strcmp(token, ss->name) && strcmp(token, ss->legacy_name)) continue; - - static_branch_disable(cgroup_subsys_enabled_key[i]); - printk(KERN_INFO "Disabling %s control group subsystem\n", - ss->name); - break; + cgroup_disable_mask |= 1 << i; } } return 1; |