Use {READ,WRITE}_ONCE() to access kvm->last_boosted_vcpu to ensure the
loads and stores are atomic. In the extremely unlikely scenario the
compiler tears the stores, it's theoretically possible for KVM to attempt
to get a vCPU using an out-of-bounds index, e.g. if the write is split
into multiple 8-bit stores, and is paired with a 32-bit load on a VM with
257 vCPUs:
CPU0 CPU1
last_boosted_vcpu = 0xff;
(last_boosted_vcpu = 0x100)
last_boosted_vcpu[15:8] = 0x01;
i = (last_boosted_vcpu = 0x1ff)
last_boosted_vcpu[7:0] = 0x00;
vcpu = kvm->vcpu_array[0x1ff];
As detected by KCSAN:
BUG: KCSAN: data-race in kvm_vcpu_on_spin [kvm] / kvm_vcpu_on_spin [kvm]
write to 0xffffc90025a92344 of 4 bytes by task 4340 on cpu 16:
kvm_vcpu_on_spin (arch/x86/kvm/../../../virt/kvm/kvm_main.c:4112) kvm
handle_pause (arch/x86/kvm/vmx/vmx.c:5929) kvm_intel
vmx_handle_exit (arch/x86/kvm/vmx/vmx.c:?
arch/x86/kvm/vmx/vmx.c:6606) kvm_intel
vcpu_run (arch/x86/kvm/x86.c:11107 arch/x86/kvm/x86.c:11211) kvm
kvm_arch_vcpu_ioctl_run (arch/x86/kvm/x86.c:?) kvm
kvm_vcpu_ioctl (arch/x86/kvm/../../../virt/kvm/kvm_main.c:?) kvm
__se_sys_ioctl (fs/ioctl.c:52 fs/ioctl.c:904 fs/ioctl.c:890)
__x64_sys_ioctl (fs/ioctl.c:890)
x64_sys_call (arch/x86/entry/syscall_64.c:33)
do_syscall_64 (arch/x86/entry/common.c:?)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
read to 0xffffc90025a92344 of 4 bytes by task 4342 on cpu 4:
kvm_vcpu_on_spin (arch/x86/kvm/../../../virt/kvm/kvm_main.c:4069) kvm
handle_pause (arch/x86/kvm/vmx/vmx.c:5929) kvm_intel
vmx_handle_exit (arch/x86/kvm/vmx/vmx.c:?
arch/x86/kvm/vmx/vmx.c:6606) kvm_intel
vcpu_run (arch/x86/kvm/x86.c:11107 arch/x86/kvm/x86.c:11211) kvm
kvm_arch_vcpu_ioctl_run (arch/x86/kvm/x86.c:?) kvm
kvm_vcpu_ioctl (arch/x86/kvm/../../../virt/kvm/kvm_main.c:?) kvm
__se_sys_ioctl (fs/ioctl.c:52 fs/ioctl.c:904 fs/ioctl.c:890)
__x64_sys_ioctl (fs/ioctl.c:890)
x64_sys_call (arch/x86/entry/syscall_64.c:33)
do_syscall_64 (arch/x86/entry/common.c:?)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
value changed: 0x00000012 -> 0x00000000
Fixes: 217ece6129f2 ("KVM: use yield_to instead of sleep in kvm_vcpu_on_spin")
Cc: stable(a)vger.kernel.org
Signed-off-by: Breno Leitao <leitao(a)debian.org>
---
Changelog:
v2:
* Reworded the git commit as suggested by Sean
* Dropped the me->kvm->last_boosted_vcpu in favor of
kvm->last_boosted_vcpu as suggested by Sean
v1:
* https://lore.kernel.org/all/20240509090146.146153-1-leitao@debian.org/
---
virt/kvm/kvm_main.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index ff0a20565f90..d9ce063c76f9 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -4066,12 +4066,13 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode)
{
struct kvm *kvm = me->kvm;
struct kvm_vcpu *vcpu;
- int last_boosted_vcpu = me->kvm->last_boosted_vcpu;
+ int last_boosted_vcpu;
unsigned long i;
int yielded = 0;
int try = 3;
int pass;
+ last_boosted_vcpu = READ_ONCE(kvm->last_boosted_vcpu);
kvm_vcpu_set_in_spin_loop(me, true);
/*
* We boost the priority of a VCPU that is runnable but not
@@ -4109,7 +4110,7 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode)
yielded = kvm_vcpu_yield_to(vcpu);
if (yielded > 0) {
- kvm->last_boosted_vcpu = i;
+ WRITE_ONCE(kvm->last_boosted_vcpu, i);
break;
} else if (yielded < 0) {
try--;
--
2.43.0
The patch titled
Subject: nilfs2: fix nilfs_empty_dir() misjudgment and long loop on I/O errors
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
nilfs2-fix-nilfs_empty_dir-misjudgment-and-long-loop-on-i-o-errors.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche…
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Ryusuke Konishi <konishi.ryusuke(a)gmail.com>
Subject: nilfs2: fix nilfs_empty_dir() misjudgment and long loop on I/O errors
Date: Tue, 4 Jun 2024 22:42:55 +0900
The error handling in nilfs_empty_dir() when a directory folio/page read
fails is incorrect, as in the old ext2 implementation, and if the
folio/page cannot be read or nilfs_check_folio() fails, it will falsely
determine the directory as empty and corrupt the file system.
In addition, since nilfs_empty_dir() does not immediately return on a
failed folio/page read, but continues to loop, this can cause a long loop
with I/O if i_size of the directory's inode is also corrupted, causing the
log writer thread to wait and hang, as reported by syzbot.
Fix these issues by making nilfs_empty_dir() immediately return a false
value (0) if it fails to get a directory folio/page.
Link: https://lkml.kernel.org/r/20240604134255.7165-1-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke(a)gmail.com>
Reported-by: syzbot+c8166c541d3971bf6c87(a)syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c8166c541d3971bf6c87
Fixes: 2ba466d74ed7 ("nilfs2: directory entry operations")
Tested-by: Ryusuke Konishi <konishi.ryusuke(a)gmail.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
fs/nilfs2/dir.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/nilfs2/dir.c~nilfs2-fix-nilfs_empty_dir-misjudgment-and-long-loop-on-i-o-errors
+++ a/fs/nilfs2/dir.c
@@ -607,7 +607,7 @@ int nilfs_empty_dir(struct inode *inode)
kaddr = nilfs_get_folio(inode, i, &folio);
if (IS_ERR(kaddr))
- continue;
+ return 0;
de = (struct nilfs_dir_entry *)kaddr;
kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1);
_
Patches currently in -mm which might be from konishi.ryusuke(a)gmail.com are
nilfs2-fix-potential-kernel-bug-due-to-lack-of-writeback-flag-waiting.patch
nilfs2-fix-nilfs_empty_dir-misjudgment-and-long-loop-on-i-o-errors.patch
Just ${Subject} since it's a fix for a potential security footgun/DOS, whereever
commit 378979e94e95 ("tcp: remove 64 KByte limit for initial tp->rcv_wnd value")
has been queued up.
Thanks!
Holger
Hi,
This seven series fix an issue reported by kernel test robot [3].
Shuah, I (as well as Kees and Sean [4]) think this should be in -next
really soon to make sure everything works fine for the v6.9 release,
which is not currently the case. I cannot test against all kselftests
though. I would prefer to let you handle this, but I guess you're not
able to do so and I'll push it on my branch without reply from you.
Even if I push it on my branch, please push it on yours too as soon as
you see this and I'll remove it from mine.
Mark, Jakub, could you please test this series?
As reported by Kernel Test Robot [1] and Sean Christopherson [2], some
tests fail since v6.9-rc1 . This is due to the use of vfork() which
introduced some side effects. Similarly, while making it more generic,
a previous commit made some Landlock file system tests flaky, and
subject to the host's file system mount configuration.
This series fixes all these side effects by replacing vfork() with
clone3() and CLONE_VFORK, which is cleaner (no arbitrary shared memory)
and makes the Kselftest framework more robust.
I tried different approaches and I found this one to be the cleaner and
less invasive for current test cases.
I successfully ran the following tests (using TEST_F and
fork/clone/clone3, and KVM_ONE_VCPU_TEST) with this series:
- kvm:fix_hypercall_test
- kvm:sync_regs_test
- kvm:userspace_msr_exit_test
- kvm:vmx_pmu_caps_test
- landlock:fs_test
- landlock:net_test
- landlock:ptrace_test
- move_mount_set_group:move_mount_set_group_test
- net/af_unix:scm_pidfd
- perf_events:remove_on_exec
- pidfd:pidfd_getfd_test
- pidfd:pidfd_setns_test
- seccomp:seccomp_bpf
- user_events:abi_test
[1] https://lore.kernel.org/oe-lkp/202403291015.1fcfa957-oliver.sang@intel.com
[2] https://lore.kernel.org/r/ZjPelW6-AbtYvslu@google.com
[3] https://lore.kernel.org/r/202405100339.vfBe0t9C-lkp@intel.com
[4] https://lore.kernel.org/r/202405061002.01D399877A@keescook
Previous versions:
v1: https://lore.kernel.org/r/20240426172252.1862930-1-mic@digikod.net
v2: https://lore.kernel.org/r/20240429130931.2394118-1-mic@digikod.net
v3: https://lore.kernel.org/r/20240429191911.2552580-1-mic@digikod.net
v4: https://lore.kernel.org/r/20240502210926.145539-1-mic@digikod.net
v5: https://lore.kernel.org/r/20240503105820.300927-1-mic@digikod.net
v6: https://lore.kernel.org/r/20240506165518.474504-1-mic@digikod.net
Regards,
Mickaël Salaün (10):
selftests/pidfd: Fix config for pidfd_setns_test
selftests/landlock: Fix FS tests when run on a private mount point
selftests/harness: Fix fixture teardown
selftests/harness: Fix interleaved scheduling leading to race
conditions
selftests/landlock: Do not allocate memory in fixture data
selftests/harness: Constify fixture variants
selftests/pidfd: Fix wrong expectation
selftests/harness: Share _metadata between forked processes
selftests/harness: Fix vfork() side effects
selftests/harness: Handle TEST_F()'s explicit exit codes
tools/testing/selftests/kselftest_harness.h | 127 +++++++++++++-----
tools/testing/selftests/landlock/fs_test.c | 83 +++++++-----
tools/testing/selftests/pidfd/config | 2 +
.../selftests/pidfd/pidfd_setns_test.c | 2 +-
4 files changed, 147 insertions(+), 67 deletions(-)
base-commit: e67572cd2204894179d89bd7b984072f19313b03
--
2.45.0
On the Qualcomm RB1 and RB2 platforms the I2C bus connected to the
LT9611UXC bridge under some circumstances can go into a state when all
transfers timeout. This causes both issues with fetching of EDID and
with updating of the bridge's firmware.
While we are debugging the issue, switch corresponding I2C bus to use
i2c-gpio driver. While using i2c-gpio no communication issues are
observed.
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov(a)linaro.org>
---
Dmitry Baryshkov (2):
arm64: dts: qcom: qrb2210-rb1: switch I2C2 to i2c-gpio
arm64: dts: qcom: qrb4210-rb2: switch I2C2 to i2c-gpio
arch/arm64/boot/dts/qcom/qrb2210-rb1.dts | 13 ++++++++++++-
arch/arm64/boot/dts/qcom/qrb4210-rb2.dts | 13 ++++++++++++-
2 files changed, 24 insertions(+), 2 deletions(-)
---
base-commit: 0e1980c40b6edfa68b6acf926bab22448a6e40c9
change-id: 20240604-rb12-i2c2g-pio-f6035fa8e022
Best regards,
--
Dmitry Baryshkov <dmitry.baryshkov(a)linaro.org>
On SC7280, in host mode, it is observed that stressing out controller
results in HC died error:
xhci-hcd.12.auto: xHCI host not responding to stop endpoint command
xhci-hcd.12.auto: xHCI host controller not responding, assume dead
xhci-hcd.12.auto: HC died; cleaning up
And at this instant only restarting the host mode fixes it. Disable
SuperSpeed instances in park mode for SC7280 to mitigate this issue.
Reported-by: Doug Anderson <dianders(a)google.com>
Cc: <stable(a)vger.kernel.org>
Fixes: bb9efa59c665 ("arm64: dts: qcom: sc7280: Add USB related nodes")
Signed-off-by: Krishna Kurapati <quic_kriskura(a)quicinc.com>
---
Removed RB/TB tag from Doug as commit text was updated.
arch/arm64/boot/dts/qcom/sc7280.dtsi | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm64/boot/dts/qcom/sc7280.dtsi b/arch/arm64/boot/dts/qcom/sc7280.dtsi
index 41f51d326111..e0d3eeb6f639 100644
--- a/arch/arm64/boot/dts/qcom/sc7280.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7280.dtsi
@@ -4131,6 +4131,7 @@ usb_1_dwc3: usb@a600000 {
iommus = <&apps_smmu 0xe0 0x0>;
snps,dis_u2_susphy_quirk;
snps,dis_enblslpm_quirk;
+ snps,parkmode-disable-ss-quirk;
phys = <&usb_1_hsphy>, <&usb_1_qmpphy QMP_USB43DP_USB3_PHY>;
phy-names = "usb2-phy", "usb3-phy";
maximum-speed = "super-speed";
--
2.34.1
On SC7180, in host mode, it is observed that stressing out controller
results in HC died error:
xhci-hcd.12.auto: xHCI host not responding to stop endpoint command
xhci-hcd.12.auto: xHCI host controller not responding, assume dead
xhci-hcd.12.auto: HC died; cleaning up
And at this instant only restarting the host mode fixes it. Disable
SuperSpeed instances in park mode for SC7180 to mitigate this issue.
Reported-by: Doug Anderson <dianders(a)google.com>
Cc: <stable(a)vger.kernel.org>
Fixes: 0b766e7fe5a2 ("arm64: dts: qcom: sc7180: Add USB related nodes")
Signed-off-by: Krishna Kurapati <quic_kriskura(a)quicinc.com>
---
Removed RB/TB tag from Doug as commit text was updated.
arch/arm64/boot/dts/qcom/sc7180.dtsi | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm64/boot/dts/qcom/sc7180.dtsi b/arch/arm64/boot/dts/qcom/sc7180.dtsi
index 2b481e20ae38..cc93b5675d5d 100644
--- a/arch/arm64/boot/dts/qcom/sc7180.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7180.dtsi
@@ -3063,6 +3063,7 @@ usb_1_dwc3: usb@a600000 {
iommus = <&apps_smmu 0x540 0>;
snps,dis_u2_susphy_quirk;
snps,dis_enblslpm_quirk;
+ snps,parkmode-disable-ss-quirk;
phys = <&usb_1_hsphy>, <&usb_1_qmpphy QMP_USB43DP_USB3_PHY>;
phy-names = "usb2-phy", "usb3-phy";
maximum-speed = "super-speed";
--
2.34.1