From: Chen Yu <yu.c.chen@intel.com>
To: reinette.chatre@intel.com
Cc: tony.luck@intel.com, james.morse@arm.com, Dave.Martin@arm.com,
babu.moger@amd.com, bp@alien8.de, tglx@linutronix.de,
dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com,
ben.horgan@arm.com, fustini@kernel.org, fenghuay@nvidia.com,
peternewman@google.com, linux-kernel@vger.kernel.org,
patches@lists.linux.dev, Chen Yu <yu.c.chen@intel.com>
Subject: Re: [PATCH v3 3/9] fs/resctrl: Fix use-after-free during unmount
Date: Thu, 28 May 2026 21:48:10 +0800 [thread overview]
Message-ID: <20260528134810.337000-1-yu.c.chen@intel.com> (raw)
In-Reply-To: <0a48bc36304da0fce4525672cca5f41c3d8ae678.1779476724.git.reinette.chatre@intel.com>
On Fri, 22 May 2026 12:15:07 -0700, Reinette Chatre wrote:
> When the mutex is released, the reader wakes up, observes that RDT_DELETED
> is not set for the default group, and dereferences the already-freed
> file private data.
I wonder if a code call sequence could be added in the commit log,
which would be helpful to quickly understand the race condition:
CPU 0 (read mon_data file) CPU 1 (umount)
-------------------------- --------------
rdtgroup_kn_lock_live()
rdtgrp = &rdtgroup_default
waitcount++
break_active_protection()
mutex_lock()
mon_put_kn_priv()
kfree(mon_data)
mutex_unlock()
mutex_lock()
rdtgrp->flags & RDT_DELETED?
// no -- never set for default
return rdtgrp
md = of->kn->priv // UAF: freed
I did not find issues in current implementation,
Reviewed-by: Chen Yu <yu.c.chen@intel.com>
next prev parent reply other threads:[~2026-05-28 13:57 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-22 19:15 [PATCH v3 0/9] x86,fs/resctrl: Fix long-standing issues Reinette Chatre
2026-05-22 19:15 ` [PATCH v3 1/9] fs/resctrl: Move functions to avoid forward references in subsequent fixes Reinette Chatre
2026-05-28 10:06 ` Ben Horgan
2026-05-22 19:15 ` [PATCH v3 2/9] fs/resctrl: Free mon_data structures on rdt_get_tree() failure Reinette Chatre
2026-05-27 15:18 ` Ben Horgan
2026-05-22 19:15 ` [PATCH v3 3/9] fs/resctrl: Fix use-after-free during unmount Reinette Chatre
2026-05-28 9:45 ` Ben Horgan
2026-05-28 16:09 ` Reinette Chatre
2026-05-28 13:48 ` Chen Yu [this message]
2026-05-28 16:09 ` Reinette Chatre
2026-05-22 19:15 ` [PATCH v3 4/9] fs/resctrl: Fix deadlock for errors during mount Reinette Chatre
2026-05-28 10:11 ` Ben Horgan
2026-05-29 14:06 ` Chen, Yu C
2026-05-29 15:53 ` Reinette Chatre
2026-05-31 8:41 ` Chen, Yu C
2026-05-22 19:15 ` [PATCH v3 5/9] fs/resctrl: Prevent use-after-free in rdtgroup_kn_put() Reinette Chatre
2026-05-28 10:51 ` Ben Horgan
2026-05-22 19:15 ` [PATCH v3 6/9] fs/resctrl: Fix pseudo-locking lifetime handling Reinette Chatre
2026-05-28 10:56 ` Ben Horgan
2026-05-28 16:10 ` Reinette Chatre
2026-05-22 19:15 ` [PATCH v3 7/9] fs/resctrl: Prevent deadlock and use-after-free in info file handlers Reinette Chatre
2026-05-22 19:15 ` [PATCH v3 8/9] x86/resctrl: Ensure domain fully initialized before placed on RCU list Reinette Chatre
2026-05-28 16:11 ` Reinette Chatre
2026-05-28 19:04 ` Babu Moger
2026-05-28 20:56 ` Reinette Chatre
2026-05-28 23:10 ` Moger, Babu
2026-05-31 8:37 ` Chen, Yu C
2026-06-01 15:40 ` Reinette Chatre
2026-05-22 19:15 ` [PATCH v3 9/9] fs/resctrl: Fix UAF from worker threads when domains are removed Reinette Chatre
2026-05-26 15:32 ` Luck, Tony
2026-05-26 17:53 ` Reinette Chatre
2026-05-26 18:27 ` Luck, Tony
2026-05-26 21:05 ` Reinette Chatre
2026-05-26 21:26 ` Luck, Tony
2026-05-27 1:49 ` Reinette Chatre
2026-05-28 16:12 ` Reinette Chatre
2026-05-28 20:08 ` [PATCH v3 0/9] x86,fs/resctrl: Fix long-standing issues Luck, Tony
2026-05-29 18:37 ` Reinette Chatre
2026-05-29 19:06 ` Luck, Tony
2026-05-29 20:19 ` Reinette Chatre
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