[PATCH v3 0/9] x86,fs/resctrl: Fix long-standing issues

[Reinette Chatre <reinette.chatre@intel.com>]

v2: https://lore.kernel.org/lkml/20260515193944.15114-1-tony.luck@intel.com/
v1: https://lore.kernel.org/all/20260508182143.14592-1-tony.luck@intel.com/

While reviewing the AET series [1] Sashiko reported a deadlock during mount,
and a use-after-free when an L3 domain is removed during CPU offline. Reinette
found a memory leak in the mount error path while refactoring code for a
solution to the mount hang.

During review of V1 of this series Sashiko found a new UAF on unmount issue
that was fixed in V2.

During review of V2 Sashiko uncovered a couple more new issues: TOCTOU
involving rdtgroup_kn_put() that may lead to UAF or double-free, double
free of pseudo-locked regions, potential deadlock between resctrl unmount and
info file readers. Sashiko also found that the CPU offline fix in V2 is flawed
in its use of is_percpu_thread().

Address all issues identified. This version is significantly different from V2
because of the additional fixes and reworking of the CPU offline fix. I do not
consider this version quite "polished" but after all changes made to address
all the issues identified by Sashiko I would like to check-in with folks (and
Sashiko) on where the fixes are headed and would appreciate any feedback.

Applies against tip/master to ensure it considers pending x86/cache changes.

[1] https://sashiko.dev/#/patchset/20260429184858.36423-1-tony.luck%40intel.com

Reinette Chatre (6):
  fs/resctrl: Fix deadlock for errors during mount
  fs/resctrl: Prevent use-after-free in rdtgroup_kn_put()
  fs/resctrl: Fix pseudo-locking lifetime handling
  fs/resctrl: Prevent deadlock and use-after-free in info file handlers
  x86/resctrl: Ensure domain fully initialized before placed on RCU list
  fs/resctrl: Fix UAF from worker threads when domains are removed

Tony Luck (3):
  fs/resctrl: Move functions to avoid forward references in subsequent
    fixes
  fs/resctrl: Free mon_data structures on rdt_get_tree() failure
  fs/resctrl: Fix use-after-free during unmount

 arch/x86/kernel/cpu/resctrl/core.c      |  18 +-
 arch/x86/kernel/cpu/resctrl/intel_aet.c |   5 +-
 fs/resctrl/ctrlmondata.c                |  38 +-
 fs/resctrl/internal.h                   |  15 +-
 fs/resctrl/monitor.c                    | 100 ++-
 fs/resctrl/pseudo_lock.c                |  44 +-
 fs/resctrl/rdtgroup.c                   | 847 +++++++++++++++---------
 7 files changed, 680 insertions(+), 387 deletions(-)

-- 
2.50.1