The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x ade81479c7dda1ce3eedb215c78bc615bbd04f06
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025020514-hacker-slouching-58c8@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From ade81479c7dda1ce3eedb215c78bc615bbd04f06 Mon Sep 17 00:00:00 2001
From: Chen Ridong <chenridong(a)huawei.com>
Date: Tue, 24 Dec 2024 02:52:38 +0000
Subject: [PATCH] memcg: fix soft lockup in the OOM process
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
A soft lockup issue was found in the product with about 56,000 tasks were
in the OOM cgroup, it was traversing them when the soft lockup was
triggered.
watchdog: BUG: soft lockup - CPU#2 stuck for 23s! [VM Thread:1503066]
CPU: 2 PID: 1503066 Comm: VM Thread Kdump: loaded Tainted: G
Hardware name: Huawei Cloud OpenStack Nova, BIOS
RIP: 0010:console_unlock+0x343/0x540
RSP: 0000:ffffb751447db9a0 EFLAGS: 00000247 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 00000000ffffffff
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000247
RBP: ffffffffafc71f90 R08: 0000000000000000 R09: 0000000000000040
R10: 0000000000000080 R11: 0000000000000000 R12: ffffffffafc74bd0
R13: ffffffffaf60a220 R14: 0000000000000247 R15: 0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2fe6ad91f0 CR3: 00000004b2076003 CR4: 0000000000360ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
vprintk_emit+0x193/0x280
printk+0x52/0x6e
dump_task+0x114/0x130
mem_cgroup_scan_tasks+0x76/0x100
dump_header+0x1fe/0x210
oom_kill_process+0xd1/0x100
out_of_memory+0x125/0x570
mem_cgroup_out_of_memory+0xb5/0xd0
try_charge+0x720/0x770
mem_cgroup_try_charge+0x86/0x180
mem_cgroup_try_charge_delay+0x1c/0x40
do_anonymous_page+0xb5/0x390
handle_mm_fault+0xc4/0x1f0
This is because thousands of processes are in the OOM cgroup, it takes a
long time to traverse all of them. As a result, this lead to soft lockup
in the OOM process.
To fix this issue, call 'cond_resched' in the 'mem_cgroup_scan_tasks'
function per 1000 iterations. For global OOM, call
'touch_softlockup_watchdog' per 1000 iterations to avoid this issue.
Link: https://lkml.kernel.org/r/20241224025238.3768787-1-chenridong@huaweicloud.c…
Fixes: 9cbb78bb3143 ("mm, memcg: introduce own oom handler to iterate only over its own threads")
Signed-off-by: Chen Ridong <chenridong(a)huawei.com>
Acked-by: Michal Hocko <mhocko(a)suse.com>
Cc: Roman Gushchin <roman.gushchin(a)linux.dev>
Cc: Johannes Weiner <hannes(a)cmpxchg.org>
Cc: Shakeel Butt <shakeelb(a)google.com>
Cc: Muchun Song <songmuchun(a)bytedance.com>
Cc: Michal Koutný <mkoutny(a)suse.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 65fb5eee1466..46f8b372d212 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1161,6 +1161,7 @@ void mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
{
struct mem_cgroup *iter;
int ret = 0;
+ int i = 0;
BUG_ON(mem_cgroup_is_root(memcg));
@@ -1169,8 +1170,12 @@ void mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
struct task_struct *task;
css_task_iter_start(&iter->css, CSS_TASK_ITER_PROCS, &it);
- while (!ret && (task = css_task_iter_next(&it)))
+ while (!ret && (task = css_task_iter_next(&it))) {
+ /* Avoid potential softlockup warning */
+ if ((++i & 1023) == 0)
+ cond_resched();
ret = fn(task, arg);
+ }
css_task_iter_end(&it);
if (ret) {
mem_cgroup_iter_break(memcg, iter);
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 1c485beb0b93..044ebab2c941 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -44,6 +44,7 @@
#include <linux/init.h>
#include <linux/mmu_notifier.h>
#include <linux/cred.h>
+#include <linux/nmi.h>
#include <asm/tlb.h>
#include "internal.h"
@@ -430,10 +431,15 @@ static void dump_tasks(struct oom_control *oc)
mem_cgroup_scan_tasks(oc->memcg, dump_task, oc);
else {
struct task_struct *p;
+ int i = 0;
rcu_read_lock();
- for_each_process(p)
+ for_each_process(p) {
+ /* Avoid potential softlockup warning */
+ if ((++i & 1023) == 0)
+ touch_softlockup_watchdog();
dump_task(p, oc);
+ }
rcu_read_unlock();
}
}
From: Roberto Sassu <roberto.sassu(a)huawei.com>
Commit 0d73a55208e9 ("ima: re-introduce own integrity cache lock")
mistakenly reverted the performance improvement introduced in commit
42a4c603198f0 ("ima: fix ima_inode_post_setattr"). The unused bit mask was
subsequently removed by commit 11c60f23ed13 ("integrity: Remove unused
macro IMA_ACTION_RULE_FLAGS").
Restore the performance improvement by introducing the new mask
IMA_NONACTION_RULE_FLAGS, equal to IMA_NONACTION_FLAGS without
IMA_NEW_FILE, which is not a rule-specific flag.
Finally, reset IMA_NONACTION_RULE_FLAGS instead of IMA_NONACTION_FLAGS in
process_measurement(), if the IMA_CHANGE_ATTR atomic flag is set (after
file metadata modification).
With this patch, new files for which metadata were modified while they are
still open, can be reopened before the last file close (when security.ima
is written), since the IMA_NEW_FILE flag is not cleared anymore. Otherwise,
appraisal fails because security.ima is missing (files with IMA_NEW_FILE
set are an exception).
Cc: stable(a)vger.kernel.org # v4.16.x
Fixes: 0d73a55208e9 ("ima: re-introduce own integrity cache lock")
Signed-off-by: Roberto Sassu <roberto.sassu(a)huawei.com>
---
security/integrity/ima/ima.h | 3 +++
security/integrity/ima/ima_main.c | 7 +++++--
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 24d09ea91b87..a4f284bd846c 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -149,6 +149,9 @@ struct ima_kexec_hdr {
#define IMA_CHECK_BLACKLIST 0x40000000
#define IMA_VERITY_REQUIRED 0x80000000
+/* Exclude non-action flags which are not rule-specific. */
+#define IMA_NONACTION_RULE_FLAGS (IMA_NONACTION_FLAGS & ~IMA_NEW_FILE)
+
#define IMA_DO_MASK (IMA_MEASURE | IMA_APPRAISE | IMA_AUDIT | \
IMA_HASH | IMA_APPRAISE_SUBMASK)
#define IMA_DONE_MASK (IMA_MEASURED | IMA_APPRAISED | IMA_AUDITED | \
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 9b87556b03a7..b028c501949c 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -269,10 +269,13 @@ static int process_measurement(struct file *file, const struct cred *cred,
mutex_lock(&iint->mutex);
if (test_and_clear_bit(IMA_CHANGE_ATTR, &iint->atomic_flags))
- /* reset appraisal flags if ima_inode_post_setattr was called */
+ /*
+ * Reset appraisal flags (action and non-action rule-specific)
+ * if ima_inode_post_setattr was called.
+ */
iint->flags &= ~(IMA_APPRAISE | IMA_APPRAISED |
IMA_APPRAISE_SUBMASK | IMA_APPRAISED_SUBMASK |
- IMA_NONACTION_FLAGS);
+ IMA_NONACTION_RULE_FLAGS);
/*
* Re-evaulate the file if either the xattr has changed or the
--
2.34.1
Hello,
we are seeing broken CPU PSI metrics across our infrastructure running
6.12, with messages like "psi: inconsistent task state!
task=1831:hackbench cpu=8 psi_flags=14 clear=0 set=4" in dmesg. I
believe commit 7d9da040575b343085287686fa902a5b2d43c7ca might fix this
issue.
psi: Fix race when task wakes up before psi_sched_switch() adjusts flags
Thanks
Paul
Direct HLT instruction execution causes #VEs for TDX VMs which is routed
to hypervisor via tdvmcall. This process renders HLT instruction
execution inatomic, so any preceding instructions like STI/MOV SS will
end up enabling interrupts before the HLT instruction is routed to the
hypervisor. This creates scenarios where interrupts could land during
HLT instruction emulation without aborting halt operation leading to
idefinite halt wait times.
Commit bfe6ed0c6727 ("x86/tdx: Add HLT support for TDX guests") already
upgraded x86_idle() to invoke tdvmcall to avoid such scenarios, but
it didn't cover pv_native_safe_halt() which can be invoked using
raw_safe_halt() from call sites like acpi_safe_halt().
raw_safe_halt() also returns with interrupts enabled so upgrade
tdx_safe_halt() to enable interrupts by default and ensure that paravirt
safe_halt() executions invoke tdx_safe_halt(). Earlier x86_idle() is now
handled via tdx_idle() which simply invokes tdvmcall while preserving
irq state.
To avoid future call sites which cause HLT instruction emulation with
irqs enabled, add a warn and fail the HLT instruction emulation.
Cc: stable(a)vger.kernel.org
Fixes: bfe6ed0c6727 ("x86/tdx: Add HLT support for TDX guests")
Signed-off-by: Vishal Annapurve <vannapurve(a)google.com>
---
Changes since V1:
1) Addressed comments from Dave H
- Comment regarding adding a check for TDX VMs in halt path is not
resolved in v2, would like feedback around better place to do so,
maybe in pv_native_safe_halt (?).
2) Added a new version of tdx_safe_halt() that will enable interrupts.
3) Previous tdx_safe_halt() implementation is moved to newly introduced
tdx_idle().
V1: https://lore.kernel.org/lkml/Z5l6L3Hen9_Y3SGC@google.com/T/
arch/x86/coco/tdx/tdx.c | 23 ++++++++++++++++++++++-
arch/x86/include/asm/tdx.h | 2 +-
arch/x86/kernel/process.c | 2 +-
3 files changed, 24 insertions(+), 3 deletions(-)
diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
index 0d9b090b4880..cc2a637dca15 100644
--- a/arch/x86/coco/tdx/tdx.c
+++ b/arch/x86/coco/tdx/tdx.c
@@ -14,6 +14,7 @@
#include <asm/ia32.h>
#include <asm/insn.h>
#include <asm/insn-eval.h>
+#include <asm/paravirt_types.h>
#include <asm/pgtable.h>
#include <asm/set_memory.h>
#include <asm/traps.h>
@@ -380,13 +381,18 @@ static int handle_halt(struct ve_info *ve)
{
const bool irq_disabled = irqs_disabled();
+ if (!irq_disabled) {
+ WARN_ONCE(1, "HLT instruction emulation unsafe with irqs enabled\n");
+ return -EIO;
+ }
+
if (__halt(irq_disabled))
return -EIO;
return ve_instr_len(ve);
}
-void __cpuidle tdx_safe_halt(void)
+void __cpuidle tdx_idle(void)
{
const bool irq_disabled = false;
@@ -397,6 +403,12 @@ void __cpuidle tdx_safe_halt(void)
WARN_ONCE(1, "HLT instruction emulation failed\n");
}
+static void __cpuidle tdx_safe_halt(void)
+{
+ tdx_idle();
+ raw_local_irq_enable();
+}
+
static int read_msr(struct pt_regs *regs, struct ve_info *ve)
{
struct tdx_module_args args = {
@@ -1083,6 +1095,15 @@ void __init tdx_early_init(void)
x86_platform.guest.enc_kexec_begin = tdx_kexec_begin;
x86_platform.guest.enc_kexec_finish = tdx_kexec_finish;
+#ifdef CONFIG_PARAVIRT_XXL
+ /*
+ * halt instruction execution is not atomic for TDX VMs as it generates
+ * #VEs, so otherwise "safe" halt invocations which cause interrupts to
+ * get enabled right after halt instruction don't work for TDX VMs.
+ */
+ pv_ops.irq.safe_halt = tdx_safe_halt;
+#endif
+
/*
* TDX intercepts the RDMSR to read the X2APIC ID in the parallel
* bringup low level code. That raises #VE which cannot be handled
diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
index eba178996d84..dd386500ab1c 100644
--- a/arch/x86/include/asm/tdx.h
+++ b/arch/x86/include/asm/tdx.h
@@ -58,7 +58,7 @@ void tdx_get_ve_info(struct ve_info *ve);
bool tdx_handle_virt_exception(struct pt_regs *regs, struct ve_info *ve);
-void tdx_safe_halt(void);
+void tdx_idle(void);
bool tdx_early_handle_ve(struct pt_regs *regs);
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index f63f8fd00a91..4083838fe4a0 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -933,7 +933,7 @@ void __init select_idle_routine(void)
static_call_update(x86_idle, mwait_idle);
} else if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST)) {
pr_info("using TDX aware idle routine\n");
- static_call_update(x86_idle, tdx_safe_halt);
+ static_call_update(x86_idle, tdx_idle);
} else {
static_call_update(x86_idle, default_idle);
}
--
2.48.1.262.g85cc9f2d1e-goog