[PATCH AUTOSEL 6.1 1/2] Grab mm lock before grabbing pt lock

[PATCH AUTOSEL 6.1 1/2] Grab mm lock before grabbing pt lock

[Sasha Levin]

From: Maksym Planeta <maksym@exostellar.io>

[ Upstream commit 6d002348789bc16e9203e9818b7a3688787e3b29 ]

Function xen_pin_page calls xen_pte_lock, which in turn grab page
table lock (ptlock). When locking, xen_pte_lock expect mm->page_table_lock
to be held before grabbing ptlock, but this does not happen when pinning
is caused by xen_mm_pin_all.

This commit addresses lockdep warning below, which shows up when
suspending a Xen VM.

[ 3680.658422] Freezing user space processes
[ 3680.660156] Freezing user space processes completed (elapsed 0.001 seconds)
[ 3680.660182] OOM killer disabled.
[ 3680.660192] Freezing remaining freezable tasks
[ 3680.661485] Freezing remaining freezable tasks completed (elapsed 0.001 seconds)
[ 3680.685254]
[ 3680.685265] ==================================
[ 3680.685269] WARNING: Nested lock was not taken
[ 3680.685274] 6.12.0+ #16 Tainted: G        W
[ 3680.685279] ----------------------------------
[ 3680.685283] migration/0/19 is trying to lock:
[ 3680.685288] ffff88800bac33c0 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: xen_pin_page+0x175/0x1d0
[ 3680.685303]
[ 3680.685303] but this task is not holding:
[ 3680.685308] init_mm.page_table_lock
[ 3680.685311]
[ 3680.685311] stack backtrace:
[ 3680.685316] CPU: 0 UID: 0 PID: 19 Comm: migration/0 Tainted: G        W          6.12.0+ #16
[ 3680.685324] Tainted: [W]=WARN
[ 3680.685328] Stopper: multi_cpu_stop+0x0/0x120 <- __stop_cpus.constprop.0+0x8c/0xd0
[ 3680.685339] Call Trace:
[ 3680.685344]  <TASK>
[ 3680.685347]  dump_stack_lvl+0x77/0xb0
[ 3680.685356]  __lock_acquire+0x917/0x2310
[ 3680.685364]  lock_acquire+0xce/0x2c0
[ 3680.685369]  ? xen_pin_page+0x175/0x1d0
[ 3680.685373]  _raw_spin_lock_nest_lock+0x2f/0x70
[ 3680.685381]  ? xen_pin_page+0x175/0x1d0
[ 3680.685386]  xen_pin_page+0x175/0x1d0
[ 3680.685390]  ? __pfx_xen_pin_page+0x10/0x10
[ 3680.685394]  __xen_pgd_walk+0x233/0x2c0
[ 3680.685401]  ? stop_one_cpu+0x91/0x100
[ 3680.685405]  __xen_pgd_pin+0x5d/0x250
[ 3680.685410]  xen_mm_pin_all+0x70/0xa0
[ 3680.685415]  xen_pv_pre_suspend+0xf/0x280
[ 3680.685420]  xen_suspend+0x57/0x1a0
[ 3680.685428]  multi_cpu_stop+0x6b/0x120
[ 3680.685432]  ? update_cpumasks_hier+0x7c/0xa60
[ 3680.685439]  ? __pfx_multi_cpu_stop+0x10/0x10
[ 3680.685443]  cpu_stopper_thread+0x8c/0x140
[ 3680.685448]  ? smpboot_thread_fn+0x20/0x1f0
[ 3680.685454]  ? __pfx_smpboot_thread_fn+0x10/0x10
[ 3680.685458]  smpboot_thread_fn+0xed/0x1f0
[ 3680.685462]  kthread+0xde/0x110
[ 3680.685467]  ? __pfx_kthread+0x10/0x10
[ 3680.685471]  ret_from_fork+0x2f/0x50
[ 3680.685478]  ? __pfx_kthread+0x10/0x10
[ 3680.685482]  ret_from_fork_asm+0x1a/0x30
[ 3680.685489]  </TASK>
[ 3680.685491]
[ 3680.685491] other info that might help us debug this:
[ 3680.685497] 1 lock held by migration/0/19:
[ 3680.685500]  #0: ffffffff8284df38 (pgd_lock){+.+.}-{3:3}, at: xen_mm_pin_all+0x14/0xa0
[ 3680.685512]
[ 3680.685512] stack backtrace:
[ 3680.685518] CPU: 0 UID: 0 PID: 19 Comm: migration/0 Tainted: G        W          6.12.0+ #16
[ 3680.685528] Tainted: [W]=WARN
[ 3680.685531] Stopper: multi_cpu_stop+0x0/0x120 <- __stop_cpus.constprop.0+0x8c/0xd0
[ 3680.685538] Call Trace:
[ 3680.685541]  <TASK>
[ 3680.685544]  dump_stack_lvl+0x77/0xb0
[ 3680.685549]  __lock_acquire+0x93c/0x2310
[ 3680.685554]  lock_acquire+0xce/0x2c0
[ 3680.685558]  ? xen_pin_page+0x175/0x1d0
[ 3680.685562]  _raw_spin_lock_nest_lock+0x2f/0x70
[ 3680.685568]  ? xen_pin_page+0x175/0x1d0
[ 3680.685572]  xen_pin_page+0x175/0x1d0
[ 3680.685578]  ? __pfx_xen_pin_page+0x10/0x10
[ 3680.685582]  __xen_pgd_walk+0x233/0x2c0
[ 3680.685588]  ? stop_one_cpu+0x91/0x100
[ 3680.685592]  __xen_pgd_pin+0x5d/0x250
[ 3680.685596]  xen_mm_pin_all+0x70/0xa0
[ 3680.685600]  xen_pv_pre_suspend+0xf/0x280
[ 3680.685607]  xen_suspend+0x57/0x1a0
[ 3680.685611]  multi_cpu_stop+0x6b/0x120
[ 3680.685615]  ? update_cpumasks_hier+0x7c/0xa60
[ 3680.685620]  ? __pfx_multi_cpu_stop+0x10/0x10
[ 3680.685625]  cpu_stopper_thread+0x8c/0x140
[ 3680.685629]  ? smpboot_thread_fn+0x20/0x1f0
[ 3680.685634]  ? __pfx_smpboot_thread_fn+0x10/0x10
[ 3680.685638]  smpboot_thread_fn+0xed/0x1f0
[ 3680.685642]  kthread+0xde/0x110
[ 3680.685645]  ? __pfx_kthread+0x10/0x10
[ 3680.685649]  ret_from_fork+0x2f/0x50
[ 3680.685654]  ? __pfx_kthread+0x10/0x10
[ 3680.685657]  ret_from_fork_asm+0x1a/0x30
[ 3680.685662]  </TASK>
[ 3680.685267] xen:grant_table: Grant tables using version 1 layout
[ 3680.685921] OOM killer enabled.
[ 3680.685934] Restarting tasks ... done.

Signed-off-by: Maksym Planeta <maksym@exostellar.io>
Reviewed-by: Juergen Gross <jgross@suse.com>
Message-ID: <20241204103516.3309112-1-maksym@exostellar.io>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/xen/mmu_pv.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index ee29fb558f2e6..74347335c56aa 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -766,6 +766,7 @@ void xen_mm_pin_all(void)
 {
 	struct page *page;
 
+	spin_lock(&init_mm.page_table_lock);
 	spin_lock(&pgd_lock);
 
 	list_for_each_entry(page, &pgd_list, lru) {
@@ -776,6 +777,7 @@ void xen_mm_pin_all(void)
 	}
 
 	spin_unlock(&pgd_lock);
+	spin_unlock(&init_mm.page_table_lock);
 }
 
 static void __init xen_mark_pinned(struct mm_struct *mm, struct page *page,
@@ -872,6 +874,7 @@ void xen_mm_unpin_all(void)
 {
 	struct page *page;
 
+	spin_lock(&init_mm.page_table_lock);
 	spin_lock(&pgd_lock);
 
 	list_for_each_entry(page, &pgd_list, lru) {
@@ -883,6 +886,7 @@ void xen_mm_unpin_all(void)
 	}
 
 	spin_unlock(&pgd_lock);
+	spin_unlock(&init_mm.page_table_lock);
 }
 
 static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
-- 
2.39.5

[PATCH AUTOSEL 6.1 2/2] selftests: gpio: gpio-sim: Fix missing chip disablements

[Sasha Levin]

From: Koichiro Den <koichiro.den@canonical.com>

[ Upstream commit f8524ac33cd452aef5384504b3264db6039a455e ]

Since upstream commit 8bd76b3d3f3a ("gpio: sim: lock up configfs that an
instantiated device depends on"), rmdir for an active virtual devices
been prohibited.

Update gpio-sim selftest to align with the change.

Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202501221006.a1ca5dfa-lkp@intel.com
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Link: https://lore.kernel.org/r/20250122043309.304621-1-koichiro.den@canonical.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/testing/selftests/gpio/gpio-sim.sh | 31 +++++++++++++++++++-----
 1 file changed, 25 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/gpio/gpio-sim.sh b/tools/testing/selftests/gpio/gpio-sim.sh
index bf67b23ed29ac..46101a800bebf 100755
--- a/tools/testing/selftests/gpio/gpio-sim.sh
+++ b/tools/testing/selftests/gpio/gpio-sim.sh
@@ -46,12 +46,6 @@ remove_chip() {
 	rmdir $CONFIGFS_DIR/$CHIP || fail "Unable to remove the chip"
 }
 
-configfs_cleanup() {
-	for CHIP in `ls $CONFIGFS_DIR/`; do
-		remove_chip $CHIP
-	done
-}
-
 create_chip() {
 	local CHIP=$1
 
@@ -105,6 +99,13 @@ disable_chip() {
 	echo 0 > $CONFIGFS_DIR/$CHIP/live || fail "Unable to disable the chip"
 }
 
+configfs_cleanup() {
+	for CHIP in `ls $CONFIGFS_DIR/`; do
+		disable_chip $CHIP
+		remove_chip $CHIP
+	done
+}
+
 configfs_chip_name() {
 	local CHIP=$1
 	local BANK=$2
@@ -181,6 +182,7 @@ create_chip chip
 create_bank chip bank
 enable_chip chip
 test -n `cat $CONFIGFS_DIR/chip/bank/chip_name` || fail "chip_name doesn't work"
+disable_chip chip
 remove_chip chip
 
 echo "1.2. chip_name returns 'none' if the chip is still pending"
@@ -195,6 +197,7 @@ create_chip chip
 create_bank chip bank
 enable_chip chip
 test -n `cat $CONFIGFS_DIR/chip/dev_name` || fail "dev_name doesn't work"
+disable_chip chip
 remove_chip chip
 
 echo "2. Creating and configuring simulated chips"
@@ -204,6 +207,7 @@ create_chip chip
 create_bank chip bank
 enable_chip chip
 test "`get_chip_num_lines chip bank`" = "1" || fail "default number of lines is not 1"
+disable_chip chip
 remove_chip chip
 
 echo "2.2. Number of lines can be specified"
@@ -212,6 +216,7 @@ create_bank chip bank
 set_num_lines chip bank 16
 enable_chip chip
 test "`get_chip_num_lines chip bank`" = "16" || fail "number of lines is not 16"
+disable_chip chip
 remove_chip chip
 
 echo "2.3. Label can be set"
@@ -220,6 +225,7 @@ create_bank chip bank
 set_label chip bank foobar
 enable_chip chip
 test "`get_chip_label chip bank`" = "foobar" || fail "label is incorrect"
+disable_chip chip
 remove_chip chip
 
 echo "2.4. Label can be left empty"
@@ -227,6 +233,7 @@ create_chip chip
 create_bank chip bank
 enable_chip chip
 test -z "`cat $CONFIGFS_DIR/chip/bank/label`" || fail "label is not empty"
+disable_chip chip
 remove_chip chip
 
 echo "2.5. Line names can be configured"
@@ -238,6 +245,7 @@ set_line_name chip bank 2 bar
 enable_chip chip
 test "`get_line_name chip bank 0`" = "foo" || fail "line name is incorrect"
 test "`get_line_name chip bank 2`" = "bar" || fail "line name is incorrect"
+disable_chip chip
 remove_chip chip
 
 echo "2.6. Line config can remain unused if offset is greater than number of lines"
@@ -248,6 +256,7 @@ set_line_name chip bank 5 foobar
 enable_chip chip
 test "`get_line_name chip bank 0`" = "" || fail "line name is incorrect"
 test "`get_line_name chip bank 1`" = "" || fail "line name is incorrect"
+disable_chip chip
 remove_chip chip
 
 echo "2.7. Line configfs directory names are sanitized"
@@ -267,6 +276,7 @@ for CHIP in $CHIPS; do
 	enable_chip $CHIP
 done
 for CHIP in $CHIPS; do
+  disable_chip $CHIP
 	remove_chip $CHIP
 done
 
@@ -278,6 +288,7 @@ echo foobar > $CONFIGFS_DIR/chip/bank/label 2> /dev/null && \
 	fail "Setting label of a live chip should fail"
 echo 8 > $CONFIGFS_DIR/chip/bank/num_lines 2> /dev/null && \
 	fail "Setting number of lines of a live chip should fail"
+disable_chip chip
 remove_chip chip
 
 echo "2.10. Can't create line items when chip is live"
@@ -285,6 +296,7 @@ create_chip chip
 create_bank chip bank
 enable_chip chip
 mkdir $CONFIGFS_DIR/chip/bank/line0 2> /dev/null && fail "Creating line item should fail"
+disable_chip chip
 remove_chip chip
 
 echo "2.11. Probe errors are propagated to user-space"
@@ -316,6 +328,7 @@ mkdir -p $CONFIGFS_DIR/chip/bank/line4/hog
 enable_chip chip
 $BASE_DIR/gpio-mockup-cdev -s 1 /dev/`configfs_chip_name chip bank` 4 2> /dev/null && \
 	fail "Setting the value of a hogged line shouldn't succeed"
+disable_chip chip
 remove_chip chip
 
 echo "3. Controlling simulated chips"
@@ -331,6 +344,7 @@ test "$?" = "1" || fail "pull set incorrectly"
 sysfs_set_pull chip bank 0 pull-down
 $BASE_DIR/gpio-mockup-cdev /dev/`configfs_chip_name chip bank` 1
 test "$?" = "0" || fail "pull set incorrectly"
+disable_chip chip
 remove_chip chip
 
 echo "3.2. Pull can be read from sysfs"
@@ -344,6 +358,7 @@ SYSFS_PATH=/sys/devices/platform/$DEVNAME/$CHIPNAME/sim_gpio0/pull
 test `cat $SYSFS_PATH` = "pull-down" || fail "reading the pull failed"
 sysfs_set_pull chip bank 0 pull-up
 test `cat $SYSFS_PATH` = "pull-up" || fail "reading the pull failed"
+disable_chip chip
 remove_chip chip
 
 echo "3.3. Incorrect input in sysfs is rejected"
@@ -355,6 +370,7 @@ DEVNAME=`configfs_dev_name chip`
 CHIPNAME=`configfs_chip_name chip bank`
 SYSFS_PATH="/sys/devices/platform/$DEVNAME/$CHIPNAME/sim_gpio0/pull"
 echo foobar > $SYSFS_PATH 2> /dev/null && fail "invalid input not detected"
+disable_chip chip
 remove_chip chip
 
 echo "3.4. Can't write to value"
@@ -365,6 +381,7 @@ DEVNAME=`configfs_dev_name chip`
 CHIPNAME=`configfs_chip_name chip bank`
 SYSFS_PATH="/sys/devices/platform/$DEVNAME/$CHIPNAME/sim_gpio0/value"
 echo 1 > $SYSFS_PATH 2> /dev/null && fail "writing to 'value' succeeded unexpectedly"
+disable_chip chip
 remove_chip chip
 
 echo "4. Simulated GPIO chips are functional"
@@ -382,6 +399,7 @@ $BASE_DIR/gpio-mockup-cdev -s 1 /dev/`configfs_chip_name chip bank` 0 &
 sleep 0.1 # FIXME Any better way?
 test `cat $SYSFS_PATH` = "1" || fail "incorrect value read from sysfs"
 kill $!
+disable_chip chip
 remove_chip chip
 
 echo "4.2. Bias settings work correctly"
@@ -394,6 +412,7 @@ CHIPNAME=`configfs_chip_name chip bank`
 SYSFS_PATH="/sys/devices/platform/$DEVNAME/$CHIPNAME/sim_gpio0/value"
 $BASE_DIR/gpio-mockup-cdev -b pull-up /dev/`configfs_chip_name chip bank` 0
 test `cat $SYSFS_PATH` = "1" || fail "bias setting does not work"
+disable_chip chip
 remove_chip chip
 
 echo "GPIO $MODULE test PASS"
-- 
2.39.5