--- /dev/null
+From 555f5c0b801b4e2115dadbdcad57ff41b0481121 Mon Sep 17 00:00:00 2001
+From: Sasha Levin <sashal@kernel.org>
+Date: Sun, 26 Jan 2020 17:31:58 -0500
+Subject: KVM: PPC: Book3S PR: Fix -Werror=return-type build failure
+
+From: David Michael <fedora.dm0@gmail.com>
+
+[ Upstream commit fd24a8624eb29d3b6b7df68096ce0321b19b03c6 ]
+
+Fixes: 3a167beac07c ("kvm: powerpc: Add kvmppc_ops callback")
+Signed-off-by: David Michael <fedora.dm0@gmail.com>
+Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+---
+ arch/powerpc/kvm/book3s_pr.c | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
+index ce4fcf76e53e9..eb86a2f26986f 100644
+--- a/arch/powerpc/kvm/book3s_pr.c
++++ b/arch/powerpc/kvm/book3s_pr.c
+@@ -2030,6 +2030,7 @@ static int kvm_vm_ioctl_get_smmu_info_pr(struct kvm *kvm,
+ {
+ /* We should not get called */
+ BUG();
++ return 0;
+ }
+ #endif /* CONFIG_PPC64 */
+
+--
+2.20.1
+
vfs-fix-do_last-regression.patch
cifs-fix-soft-mounts-hanging-in-the-reconnect-code.patch
+x86-resctrl-fix-a-deadlock-due-to-inaccurate-referen.patch
+x86-resctrl-fix-use-after-free-when-deleting-resourc.patch
+x86-resctrl-fix-use-after-free-due-to-inaccurate-ref.patch
+kvm-ppc-book3s-pr-fix-werror-return-type-build-failu.patch
--- /dev/null
+From aa217405f559c7c32079f5bfb5c92a85bca037c8 Mon Sep 17 00:00:00 2001
+From: Sasha Levin <sashal@kernel.org>
+Date: Thu, 9 Jan 2020 00:28:05 +0800
+Subject: x86/resctrl: Fix a deadlock due to inaccurate reference
+
+From: Xiaochen Shen <xiaochen.shen@intel.com>
+
+[ Upstream commit 334b0f4e9b1b4a1d475f803419d202f6c5e4d18e ]
+
+There is a race condition which results in a deadlock when rmdir and
+mkdir execute concurrently:
+
+$ ls /sys/fs/resctrl/c1/mon_groups/m1/
+cpus cpus_list mon_data tasks
+
+Thread 1: rmdir /sys/fs/resctrl/c1
+Thread 2: mkdir /sys/fs/resctrl/c1/mon_groups/m1
+
+3 locks held by mkdir/48649:
+ #0: (sb_writers#17){.+.+}, at: [<ffffffffb4ca2aa0>] mnt_want_write+0x20/0x50
+ #1: (&type->i_mutex_dir_key#8/1){+.+.}, at: [<ffffffffb4c8c13b>] filename_create+0x7b/0x170
+ #2: (rdtgroup_mutex){+.+.}, at: [<ffffffffb4a4389d>] rdtgroup_kn_lock_live+0x3d/0x70
+
+4 locks held by rmdir/48652:
+ #0: (sb_writers#17){.+.+}, at: [<ffffffffb4ca2aa0>] mnt_want_write+0x20/0x50
+ #1: (&type->i_mutex_dir_key#8/1){+.+.}, at: [<ffffffffb4c8c3cf>] do_rmdir+0x13f/0x1e0
+ #2: (&type->i_mutex_dir_key#8){++++}, at: [<ffffffffb4c86d5d>] vfs_rmdir+0x4d/0x120
+ #3: (rdtgroup_mutex){+.+.}, at: [<ffffffffb4a4389d>] rdtgroup_kn_lock_live+0x3d/0x70
+
+Thread 1 is deleting control group "c1". Holding rdtgroup_mutex,
+kernfs_remove() removes all kernfs nodes under directory "c1"
+recursively, then waits for sub kernfs node "mon_groups" to drop active
+reference.
+
+Thread 2 is trying to create a subdirectory "m1" in the "mon_groups"
+directory. The wrapper kernfs_iop_mkdir() takes an active reference to
+the "mon_groups" directory but the code drops the active reference to
+the parent directory "c1" instead.
+
+As a result, Thread 1 is blocked on waiting for active reference to drop
+and never release rdtgroup_mutex, while Thread 2 is also blocked on
+trying to get rdtgroup_mutex.
+
+Thread 1 (rdtgroup_rmdir) Thread 2 (rdtgroup_mkdir)
+(rmdir /sys/fs/resctrl/c1) (mkdir /sys/fs/resctrl/c1/mon_groups/m1)
+------------------------- -------------------------
+ kernfs_iop_mkdir
+ /*
+ * kn: "m1", parent_kn: "mon_groups",
+ * prgrp_kn: parent_kn->parent: "c1",
+ *
+ * "mon_groups", parent_kn->active++: 1
+ */
+ kernfs_get_active(parent_kn)
+kernfs_iop_rmdir
+ /* "c1", kn->active++ */
+ kernfs_get_active(kn)
+
+ rdtgroup_kn_lock_live
+ atomic_inc(&rdtgrp->waitcount)
+ /* "c1", kn->active-- */
+ kernfs_break_active_protection(kn)
+ mutex_lock
+
+ rdtgroup_rmdir_ctrl
+ free_all_child_rdtgrp
+ sentry->flags = RDT_DELETED
+
+ rdtgroup_ctrl_remove
+ rdtgrp->flags = RDT_DELETED
+ kernfs_get(kn)
+ kernfs_remove(rdtgrp->kn)
+ __kernfs_remove
+ /* "mon_groups", sub_kn */
+ atomic_add(KN_DEACTIVATED_BIAS, &sub_kn->active)
+ kernfs_drain(sub_kn)
+ /*
+ * sub_kn->active == KN_DEACTIVATED_BIAS + 1,
+ * waiting on sub_kn->active to drop, but it
+ * never drops in Thread 2 which is blocked
+ * on getting rdtgroup_mutex.
+ */
+Thread 1 hangs here ---->
+ wait_event(sub_kn->active == KN_DEACTIVATED_BIAS)
+ ...
+ rdtgroup_mkdir
+ rdtgroup_mkdir_mon(parent_kn, prgrp_kn)
+ mkdir_rdt_prepare(parent_kn, prgrp_kn)
+ rdtgroup_kn_lock_live(prgrp_kn)
+ atomic_inc(&rdtgrp->waitcount)
+ /*
+ * "c1", prgrp_kn->active--
+ *
+ * The active reference on "c1" is
+ * dropped, but not matching the
+ * actual active reference taken
+ * on "mon_groups", thus causing
+ * Thread 1 to wait forever while
+ * holding rdtgroup_mutex.
+ */
+ kernfs_break_active_protection(
+ prgrp_kn)
+ /*
+ * Trying to get rdtgroup_mutex
+ * which is held by Thread 1.
+ */
+Thread 2 hangs here ----> mutex_lock
+ ...
+
+The problem is that the creation of a subdirectory in the "mon_groups"
+directory incorrectly releases the active protection of its parent
+directory instead of itself before it starts waiting for rdtgroup_mutex.
+This is triggered by the rdtgroup_mkdir() flow calling
+rdtgroup_kn_lock_live()/rdtgroup_kn_unlock() with kernfs node of the
+parent control group ("c1") as argument. It should be called with kernfs
+node "mon_groups" instead. What is currently missing is that the
+kn->priv of "mon_groups" is NULL instead of pointing to the rdtgrp.
+
+Fix it by pointing kn->priv to rdtgrp when "mon_groups" is created. Then
+it could be passed to rdtgroup_kn_lock_live()/rdtgroup_kn_unlock()
+instead. And then it operates on the same rdtgroup structure but handles
+the active reference of kernfs node "mon_groups" to prevent deadlock.
+The same changes are also made to the "mon_data" directories.
+
+This results in some unused function parameters that will be cleaned up
+in follow-up patch as the focus here is on the fix only in support of
+backporting efforts.
+
+Fixes: c7d9aac61311 ("x86/intel_rdt/cqm: Add mkdir support for RDT monitoring")
+Suggested-by: Reinette Chatre <reinette.chatre@intel.com>
+Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com>
+Signed-off-by: Borislav Petkov <bp@suse.de>
+Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
+Reviewed-by: Tony Luck <tony.luck@intel.com>
+Acked-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: stable@vger.kernel.org
+Link: https://lkml.kernel.org/r/1578500886-21771-4-git-send-email-xiaochen.shen@intel.com
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+---
+ arch/x86/kernel/cpu/resctrl/rdtgroup.c | 16 ++++++++--------
+ 1 file changed, 8 insertions(+), 8 deletions(-)
+
+diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+index dac7209a07084..e4da26325e3ea 100644
+--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
++++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+@@ -1970,7 +1970,7 @@ static int rdt_get_tree(struct fs_context *fc)
+
+ if (rdt_mon_capable) {
+ ret = mongroup_create_dir(rdtgroup_default.kn,
+- NULL, "mon_groups",
++ &rdtgroup_default, "mon_groups",
+ &kn_mongrp);
+ if (ret < 0)
+ goto out_info;
+@@ -2446,7 +2446,7 @@ static int mkdir_mondata_all(struct kernfs_node *parent_kn,
+ /*
+ * Create the mon_data directory first.
+ */
+- ret = mongroup_create_dir(parent_kn, NULL, "mon_data", &kn);
++ ret = mongroup_create_dir(parent_kn, prgrp, "mon_data", &kn);
+ if (ret)
+ return ret;
+
+@@ -2645,7 +2645,7 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
+ uint files = 0;
+ int ret;
+
+- prdtgrp = rdtgroup_kn_lock_live(prgrp_kn);
++ prdtgrp = rdtgroup_kn_lock_live(parent_kn);
+ if (!prdtgrp) {
+ ret = -ENODEV;
+ goto out_unlock;
+@@ -2718,7 +2718,7 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
+ kernfs_activate(kn);
+
+ /*
+- * The caller unlocks the prgrp_kn upon success.
++ * The caller unlocks the parent_kn upon success.
+ */
+ return 0;
+
+@@ -2729,7 +2729,7 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
+ out_free_rgrp:
+ kfree(rdtgrp);
+ out_unlock:
+- rdtgroup_kn_unlock(prgrp_kn);
++ rdtgroup_kn_unlock(parent_kn);
+ return ret;
+ }
+
+@@ -2767,7 +2767,7 @@ static int rdtgroup_mkdir_mon(struct kernfs_node *parent_kn,
+ */
+ list_add_tail(&rdtgrp->mon.crdtgrp_list, &prgrp->mon.crdtgrp_list);
+
+- rdtgroup_kn_unlock(prgrp_kn);
++ rdtgroup_kn_unlock(parent_kn);
+ return ret;
+ }
+
+@@ -2810,7 +2810,7 @@ static int rdtgroup_mkdir_ctrl_mon(struct kernfs_node *parent_kn,
+ * Create an empty mon_groups directory to hold the subset
+ * of tasks and cpus to monitor.
+ */
+- ret = mongroup_create_dir(kn, NULL, "mon_groups", NULL);
++ ret = mongroup_create_dir(kn, rdtgrp, "mon_groups", NULL);
+ if (ret) {
+ rdt_last_cmd_puts("kernfs subdir error\n");
+ goto out_del_list;
+@@ -2826,7 +2826,7 @@ static int rdtgroup_mkdir_ctrl_mon(struct kernfs_node *parent_kn,
+ out_common_fail:
+ mkdir_rdt_prepare_clean(rdtgrp);
+ out_unlock:
+- rdtgroup_kn_unlock(prgrp_kn);
++ rdtgroup_kn_unlock(parent_kn);
+ return ret;
+ }
+
+--
+2.20.1
+
--- /dev/null
+From 2e78cbc024e8bac1957a2a93c9f9e9d39d2600ec Mon Sep 17 00:00:00 2001
+From: Sasha Levin <sashal@kernel.org>
+Date: Thu, 9 Jan 2020 00:28:04 +0800
+Subject: x86/resctrl: Fix use-after-free due to inaccurate refcount of
+ rdtgroup
+
+From: Xiaochen Shen <xiaochen.shen@intel.com>
+
+[ Upstream commit 074fadee59ee7a9d2b216e9854bd4efb5dad679f ]
+
+There is a race condition in the following scenario which results in an
+use-after-free issue when reading a monitoring file and deleting the
+parent ctrl_mon group concurrently:
+
+Thread 1 calls atomic_inc() to take refcount of rdtgrp and then calls
+kernfs_break_active_protection() to drop the active reference of kernfs
+node in rdtgroup_kn_lock_live().
+
+In Thread 2, kernfs_remove() is a blocking routine. It waits on all sub
+kernfs nodes to drop the active reference when removing all subtree
+kernfs nodes recursively. Thread 2 could block on kernfs_remove() until
+Thread 1 calls kernfs_break_active_protection(). Only after
+kernfs_remove() completes the refcount of rdtgrp could be trusted.
+
+Before Thread 1 calls atomic_inc() and kernfs_break_active_protection(),
+Thread 2 could call kfree() when the refcount of rdtgrp (sentry) is 0
+instead of 1 due to the race.
+
+In Thread 1, in rdtgroup_kn_unlock(), referring to earlier rdtgrp memory
+(rdtgrp->waitcount) which was already freed in Thread 2 results in
+use-after-free issue.
+
+Thread 1 (rdtgroup_mondata_show) Thread 2 (rdtgroup_rmdir)
+-------------------------------- -------------------------
+rdtgroup_kn_lock_live
+ /*
+ * kn active protection until
+ * kernfs_break_active_protection(kn)
+ */
+ rdtgrp = kernfs_to_rdtgroup(kn)
+ rdtgroup_kn_lock_live
+ atomic_inc(&rdtgrp->waitcount)
+ mutex_lock
+ rdtgroup_rmdir_ctrl
+ free_all_child_rdtgrp
+ /*
+ * sentry->waitcount should be 1
+ * but is 0 now due to the race.
+ */
+ kfree(sentry)*[1]
+ /*
+ * Only after kernfs_remove()
+ * completes, the refcount of
+ * rdtgrp could be trusted.
+ */
+ atomic_inc(&rdtgrp->waitcount)
+ /* kn->active-- */
+ kernfs_break_active_protection(kn)
+ rdtgroup_ctrl_remove
+ rdtgrp->flags = RDT_DELETED
+ /*
+ * Blocking routine, wait for
+ * all sub kernfs nodes to drop
+ * active reference in
+ * kernfs_break_active_protection.
+ */
+ kernfs_remove(rdtgrp->kn)
+ rdtgroup_kn_unlock
+ mutex_unlock
+ atomic_dec_and_test(
+ &rdtgrp->waitcount)
+ && (flags & RDT_DELETED)
+ kernfs_unbreak_active_protection(kn)
+ kfree(rdtgrp)
+ mutex_lock
+mon_event_read
+rdtgroup_kn_unlock
+ mutex_unlock
+ /*
+ * Use-after-free: refer to earlier rdtgrp
+ * memory which was freed in [1].
+ */
+ atomic_dec_and_test(&rdtgrp->waitcount)
+ && (flags & RDT_DELETED)
+ /* kn->active++ */
+ kernfs_unbreak_active_protection(kn)
+ kfree(rdtgrp)
+
+Fix it by moving free_all_child_rdtgrp() to after kernfs_remove() in
+rdtgroup_rmdir_ctrl() to ensure it has the accurate refcount of rdtgrp.
+
+Fixes: f3cbeacaa06e ("x86/intel_rdt/cqm: Add rmdir support")
+Suggested-by: Reinette Chatre <reinette.chatre@intel.com>
+Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com>
+Signed-off-by: Borislav Petkov <bp@suse.de>
+Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
+Reviewed-by: Tony Luck <tony.luck@intel.com>
+Acked-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: stable@vger.kernel.org
+Link: https://lkml.kernel.org/r/1578500886-21771-3-git-send-email-xiaochen.shen@intel.com
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+---
+ arch/x86/kernel/cpu/resctrl/rdtgroup.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+index c7564294a12a8..954fd048ad9bd 100644
+--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
++++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+@@ -2960,13 +2960,13 @@ static int rdtgroup_rmdir_ctrl(struct kernfs_node *kn, struct rdtgroup *rdtgrp,
+ closid_free(rdtgrp->closid);
+ free_rmid(rdtgrp->mon.rmid);
+
++ rdtgroup_ctrl_remove(kn, rdtgrp);
++
+ /*
+ * Free all the child monitor group rmids.
+ */
+ free_all_child_rdtgrp(rdtgrp);
+
+- rdtgroup_ctrl_remove(kn, rdtgrp);
+-
+ return 0;
+ }
+
+--
+2.20.1
+
--- /dev/null
+From 376679d234ef92f4cbff65d2b1302a08d5ff032e Mon Sep 17 00:00:00 2001
+From: Sasha Levin <sashal@kernel.org>
+Date: Thu, 9 Jan 2020 00:28:03 +0800
+Subject: x86/resctrl: Fix use-after-free when deleting resource groups
+
+From: Xiaochen Shen <xiaochen.shen@intel.com>
+
+[ Upstream commit b8511ccc75c033f6d54188ea4df7bf1e85778740 ]
+
+A resource group (rdtgrp) contains a reference count (rdtgrp->waitcount)
+that indicates how many waiters expect this rdtgrp to exist. Waiters
+could be waiting on rdtgroup_mutex or some work sitting on a task's
+workqueue for when the task returns from kernel mode or exits.
+
+The deletion of a rdtgrp is intended to have two phases:
+
+ (1) while holding rdtgroup_mutex the necessary cleanup is done and
+ rdtgrp->flags is set to RDT_DELETED,
+
+ (2) after releasing the rdtgroup_mutex, the rdtgrp structure is freed
+ only if there are no waiters and its flag is set to RDT_DELETED. Upon
+ gaining access to rdtgroup_mutex or rdtgrp, a waiter is required to check
+ for the RDT_DELETED flag.
+
+When unmounting the resctrl file system or deleting ctrl_mon groups,
+all of the subdirectories are removed and the data structure of rdtgrp
+is forcibly freed without checking rdtgrp->waitcount. If at this point
+there was a waiter on rdtgrp then a use-after-free issue occurs when the
+waiter starts running and accesses the rdtgrp structure it was waiting
+on.
+
+See kfree() calls in [1], [2] and [3] in these two call paths in
+following scenarios:
+(1) rdt_kill_sb() -> rmdir_all_sub() -> free_all_child_rdtgrp()
+(2) rdtgroup_rmdir() -> rdtgroup_rmdir_ctrl() -> free_all_child_rdtgrp()
+
+There are several scenarios that result in use-after-free issue in
+following:
+
+Scenario 1:
+-----------
+In Thread 1, rdtgroup_tasks_write() adds a task_work callback
+move_myself(). If move_myself() is scheduled to execute after Thread 2
+rdt_kill_sb() is finished, referring to earlier rdtgrp memory
+(rdtgrp->waitcount) which was already freed in Thread 2 results in
+use-after-free issue.
+
+Thread 1 (rdtgroup_tasks_write) Thread 2 (rdt_kill_sb)
+------------------------------- ----------------------
+rdtgroup_kn_lock_live
+ atomic_inc(&rdtgrp->waitcount)
+ mutex_lock
+rdtgroup_move_task
+ __rdtgroup_move_task
+ /*
+ * Take an extra refcount, so rdtgrp cannot be freed
+ * before the call back move_myself has been invoked
+ */
+ atomic_inc(&rdtgrp->waitcount)
+ /* Callback move_myself will be scheduled for later */
+ task_work_add(move_myself)
+rdtgroup_kn_unlock
+ mutex_unlock
+ atomic_dec_and_test(&rdtgrp->waitcount)
+ && (flags & RDT_DELETED)
+ mutex_lock
+ rmdir_all_sub
+ /*
+ * sentry and rdtgrp are freed
+ * without checking refcount
+ */
+ free_all_child_rdtgrp
+ kfree(sentry)*[1]
+ kfree(rdtgrp)*[2]
+ mutex_unlock
+/*
+ * Callback is scheduled to execute
+ * after rdt_kill_sb is finished
+ */
+move_myself
+ /*
+ * Use-after-free: refer to earlier rdtgrp
+ * memory which was freed in [1] or [2].
+ */
+ atomic_dec_and_test(&rdtgrp->waitcount)
+ && (flags & RDT_DELETED)
+ kfree(rdtgrp)
+
+Scenario 2:
+-----------
+In Thread 1, rdtgroup_tasks_write() adds a task_work callback
+move_myself(). If move_myself() is scheduled to execute after Thread 2
+rdtgroup_rmdir() is finished, referring to earlier rdtgrp memory
+(rdtgrp->waitcount) which was already freed in Thread 2 results in
+use-after-free issue.
+
+Thread 1 (rdtgroup_tasks_write) Thread 2 (rdtgroup_rmdir)
+------------------------------- -------------------------
+rdtgroup_kn_lock_live
+ atomic_inc(&rdtgrp->waitcount)
+ mutex_lock
+rdtgroup_move_task
+ __rdtgroup_move_task
+ /*
+ * Take an extra refcount, so rdtgrp cannot be freed
+ * before the call back move_myself has been invoked
+ */
+ atomic_inc(&rdtgrp->waitcount)
+ /* Callback move_myself will be scheduled for later */
+ task_work_add(move_myself)
+rdtgroup_kn_unlock
+ mutex_unlock
+ atomic_dec_and_test(&rdtgrp->waitcount)
+ && (flags & RDT_DELETED)
+ rdtgroup_kn_lock_live
+ atomic_inc(&rdtgrp->waitcount)
+ mutex_lock
+ rdtgroup_rmdir_ctrl
+ free_all_child_rdtgrp
+ /*
+ * sentry is freed without
+ * checking refcount
+ */
+ kfree(sentry)*[3]
+ rdtgroup_ctrl_remove
+ rdtgrp->flags = RDT_DELETED
+ rdtgroup_kn_unlock
+ mutex_unlock
+ atomic_dec_and_test(
+ &rdtgrp->waitcount)
+ && (flags & RDT_DELETED)
+ kfree(rdtgrp)
+/*
+ * Callback is scheduled to execute
+ * after rdt_kill_sb is finished
+ */
+move_myself
+ /*
+ * Use-after-free: refer to earlier rdtgrp
+ * memory which was freed in [3].
+ */
+ atomic_dec_and_test(&rdtgrp->waitcount)
+ && (flags & RDT_DELETED)
+ kfree(rdtgrp)
+
+If CONFIG_DEBUG_SLAB=y, Slab corruption on kmalloc-2k can be observed
+like following. Note that "0x6b" is POISON_FREE after kfree(). The
+corrupted bits "0x6a", "0x64" at offset 0x424 correspond to
+waitcount member of struct rdtgroup which was freed:
+
+ Slab corruption (Not tainted): kmalloc-2k start=ffff9504c5b0d000, len=2048
+ 420: 6b 6b 6b 6b 6a 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkjkkkkkkkkkkk
+ Single bit error detected. Probably bad RAM.
+ Run memtest86+ or a similar memory test tool.
+ Next obj: start=ffff9504c5b0d800, len=2048
+ 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
+ 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
+
+ Slab corruption (Not tainted): kmalloc-2k start=ffff9504c58ab800, len=2048
+ 420: 6b 6b 6b 6b 64 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkdkkkkkkkkkkk
+ Prev obj: start=ffff9504c58ab000, len=2048
+ 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
+ 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
+
+Fix this by taking reference count (waitcount) of rdtgrp into account in
+the two call paths that currently do not do so. Instead of always
+freeing the resource group it will only be freed if there are no waiters
+on it. If there are waiters, the resource group will have its flags set
+to RDT_DELETED.
+
+It will be left to the waiter to free the resource group when it starts
+running and finding that it was the last waiter and the resource group
+has been removed (rdtgrp->flags & RDT_DELETED) since. (1) rdt_kill_sb()
+-> rmdir_all_sub() -> free_all_child_rdtgrp() (2) rdtgroup_rmdir() ->
+rdtgroup_rmdir_ctrl() -> free_all_child_rdtgrp()
+
+Fixes: f3cbeacaa06e ("x86/intel_rdt/cqm: Add rmdir support")
+Fixes: 60cf5e101fd4 ("x86/intel_rdt: Add mkdir to resctrl file system")
+Suggested-by: Reinette Chatre <reinette.chatre@intel.com>
+Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com>
+Signed-off-by: Borislav Petkov <bp@suse.de>
+Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
+Reviewed-by: Tony Luck <tony.luck@intel.com>
+Acked-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: stable@vger.kernel.org
+Link: https://lkml.kernel.org/r/1578500886-21771-2-git-send-email-xiaochen.shen@intel.com
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+---
+ arch/x86/kernel/cpu/resctrl/rdtgroup.c | 12 ++++++++++--
+ 1 file changed, 10 insertions(+), 2 deletions(-)
+
+diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+index e4da26325e3ea..c7564294a12a8 100644
+--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
++++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+@@ -2205,7 +2205,11 @@ static void free_all_child_rdtgrp(struct rdtgroup *rdtgrp)
+ list_for_each_entry_safe(sentry, stmp, head, mon.crdtgrp_list) {
+ free_rmid(sentry->mon.rmid);
+ list_del(&sentry->mon.crdtgrp_list);
+- kfree(sentry);
++
++ if (atomic_read(&sentry->waitcount) != 0)
++ sentry->flags = RDT_DELETED;
++ else
++ kfree(sentry);
+ }
+ }
+
+@@ -2243,7 +2247,11 @@ static void rmdir_all_sub(void)
+
+ kernfs_remove(rdtgrp->kn);
+ list_del(&rdtgrp->rdtgroup_list);
+- kfree(rdtgrp);
++
++ if (atomic_read(&rdtgrp->waitcount) != 0)
++ rdtgrp->flags = RDT_DELETED;
++ else
++ kfree(rdtgrp);
+ }
+ /* Notify online CPUs to update per cpu storage and PQR_ASSOC MSR */
+ update_closid_rmid(cpu_online_mask, &rdtgroup_default);
+--
+2.20.1
+
projects / thirdparty / kernel / stable-queue.git / commitdiff
