diff options
author | Xiaochen Shen <xiaochen.shen@intel.com> | 2019-10-29 13:25:02 +0800 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-12-05 15:36:55 +0100 |
commit | 222b0c56d2849a48b3ba57ff08c64f5591e72a74 (patch) | |
tree | 2579bed6b386ba8b1355c27175994a3806d9f267 /arch/x86 | |
parent | d0840f62f1a51df5853b3f22ffc5be91438304db (diff) |
x86/resctrl: Prevent NULL pointer dereference when reading mondata
[ Upstream commit 26467b0f8407cbd628fa5b7bcfd156e772004155 ]
When a mon group is being deleted, rdtgrp->flags is set to RDT_DELETED
in rdtgroup_rmdir_mon() firstly. The structure of rdtgrp will be freed
until rdtgrp->waitcount is dropped to 0 in rdtgroup_kn_unlock() later.
During the window of deleting a mon group, if an application calls
rdtgroup_mondata_show() to read mondata under this mon group,
'rdtgrp' returned from rdtgroup_kn_lock_live() is a NULL pointer when
rdtgrp->flags is RDT_DELETED. And then 'rdtgrp' is passed in this path:
rdtgroup_mondata_show() --> mon_event_read() --> mon_event_count().
Thus it results in NULL pointer dereference in mon_event_count().
Check 'rdtgrp' in rdtgroup_mondata_show(), and return -ENOENT
immediately when reading mondata during the window of deleting a mon
group.
Fixes: d89b7379015f ("x86/intel_rdt/cqm: Add mon_data")
Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: pei.p.jia@intel.com
Cc: Reinette Chatre <reinette.chatre@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/1572326702-27577-1-git-send-email-xiaochen.shen@intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/x86')
-rw-r--r-- | arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c b/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c index f6ea94f8954a..f892cb0b485e 100644 --- a/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c +++ b/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c @@ -313,6 +313,10 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg) int ret = 0; rdtgrp = rdtgroup_kn_lock_live(of->kn); + if (!rdtgrp) { + ret = -ENOENT; + goto out; + } md.priv = of->kn->priv; resid = md.u.rid; |