diff options
Diffstat (limited to 'security-device_cgroup-fix-RCU-lockdep-splat.patch')
| -rw-r--r-- | security-device_cgroup-fix-RCU-lockdep-splat.patch | 71 |
1 files changed, 0 insertions, 71 deletions
diff --git a/security-device_cgroup-fix-RCU-lockdep-splat.patch b/security-device_cgroup-fix-RCU-lockdep-splat.patch deleted file mode 100644 index 0ecacdfe4..000000000 --- a/security-device_cgroup-fix-RCU-lockdep-splat.patch +++ /dev/null @@ -1,71 +0,0 @@ -From 85f4e5ec7bbb5f8d7cc023a12af39d76c05cd204 Mon Sep 17 00:00:00 2001 -From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> -Date: Wed, 2 Sep 2015 17:14:33 -0700 -Subject: [PATCH] security: device_cgroup: fix RCU lockdep splat - -On Wed, Sep 02, 2015 at 12:24:50PM -0400, Tejun Heo wrote: -> cc'ing Paul. -> -> On Wed, Sep 02, 2015 at 08:12:28AM -0500, Felipe Balbi wrote: -> > while booting AM437x device, the following splat -> > triggered: -> > -> > [ 12.005238] =============================== -> > [ 12.009749] [ INFO: suspicious RCU usage. ] -> > [ 12.014116] 4.2.0-next-20150831 #1154 Not tainted -> > [ 12.019050] ------------------------------- -> > [ 12.023408] security/device_cgroup.c:405 device_cgroup:verify_new_ex called without proper synchronization! -> ... -> > [ 12.128326] [<c0317a04>] (verify_new_ex) from [<c0317f50>] (devcgroup_access_write+0x374/0x658) -> > [ 12.137426] [<c0317f50>] (devcgroup_access_write) from [<c00d2800>] (cgroup_file_write+0x28/0x1bc) -> > [ 12.146796] [<c00d2800>] (cgroup_file_write) from [<c01f1670>] (kernfs_fop_write+0xc0/0x1b8) -> > [ 12.155620] [<c01f1670>] (kernfs_fop_write) from [<c0177c94>] (__vfs_write+0x1c/0xd8) -> > [ 12.163783] [<c0177c94>] (__vfs_write) from [<c0178594>] (vfs_write+0x90/0x16c) -> > [ 12.171426] [<c0178594>] (vfs_write) from [<c0178db4>] (SyS_write+0x44/0x9c) -> > [ 12.178806] [<c0178db4>] (SyS_write) from [<c000f680>] (ret_fast_syscall+0x0/0x1c) -> -> This shouldn't be happening because devcgroup_access_write() always -> grabs devcgroup_mutex. Looking at the log, the culprit seems to be -> f78f5b90c4ff ("rcu: Rename rcu_lockdep_assert() to -> RCU_LOCKDEP_WARN()"). It missed the bang for the second test while -> inverting it, so adding rcu_read_lock() isn't the right fix here. -> -> Paul, can you please fix it? - -Gah! Please see below. - - Thanx, Paul - ------------------------------------------------------------------------- - -security/device_cgroup: Fix RCU_LOCKDEP_WARN() condition - -f78f5b90c4ff ("rcu: Rename rcu_lockdep_assert() to RCU_LOCKDEP_WARN()") -introduced a bug by incorrectly inverting the condition when moving from -rcu_lockdep_assert() to RCU_LOCKDEP_WARN(). This commit therefore fixes -the inversion. - -Reported-by: Felipe Balbi <balbi@ti.com> -Reported-by: Tejun Heo <tj@kernel.org> -Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> -Cc: Serge Hallyn <serge@hallyn.com> ---- - security/device_cgroup.c | 2 +- - 1 file changed, 1 insertion(+), 1 deletion(-) - -diff --git a/security/device_cgroup.c b/security/device_cgroup.c -index 73455089feef..03c1652c9a1f 100644 ---- a/security/device_cgroup.c -+++ b/security/device_cgroup.c -@@ -401,7 +401,7 @@ static bool verify_new_ex(struct dev_cgroup *dev_cgroup, - bool match = false; - - RCU_LOCKDEP_WARN(!rcu_read_lock_held() && -- lockdep_is_held(&devcgroup_mutex), -+ !lockdep_is_held(&devcgroup_mutex), - "device_cgroup:verify_new_ex called without proper synchronization"); - - if (dev_cgroup->behavior == DEVCG_DEFAULT_ALLOW) { --- -2.4.3 - |