The patch below does not apply to the 4.19-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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 7adacf5eb2d2048045d9fd8fdab861fd9e7e2e96 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini(a)redhat.com>
Date: Wed, 4 Dec 2019 15:50:27 +0100
Subject: [PATCH] KVM: x86: use CPUID to locate host page table reserved bits
The comment in kvm_get_shadow_phys_bits refers to MKTME, but the same is actually
true of SME and SEV. Just use CPUID[0x8000_0008].EAX[7:0] unconditionally if
available, it is simplest and works even if memory is not encrypted.
Cc: stable(a)vger.kernel.org
Reported-by: Tom Lendacky <thomas.lendacky(a)amd.com>
Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com>
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 6f92b40d798c..1e4ee4f8de5f 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -538,16 +538,20 @@ EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes);
static u8 kvm_get_shadow_phys_bits(void)
{
/*
- * boot_cpu_data.x86_phys_bits is reduced when MKTME is detected
- * in CPU detection code, but MKTME treats those reduced bits as
- * 'keyID' thus they are not reserved bits. Therefore for MKTME
- * we should still return physical address bits reported by CPUID.
+ * boot_cpu_data.x86_phys_bits is reduced when MKTME or SME are detected
+ * in CPU detection code, but the processor treats those reduced bits as
+ * 'keyID' thus they are not reserved bits. Therefore KVM needs to look at
+ * the physical address bits reported by CPUID.
*/
- if (!boot_cpu_has(X86_FEATURE_TME) ||
- WARN_ON_ONCE(boot_cpu_data.extended_cpuid_level < 0x80000008))
- return boot_cpu_data.x86_phys_bits;
+ if (likely(boot_cpu_data.extended_cpuid_level >= 0x80000008))
+ return cpuid_eax(0x80000008) & 0xff;
- return cpuid_eax(0x80000008) & 0xff;
+ /*
+ * Quite weird to have VMX or SVM but not MAXPHYADDR; probably a VM with
+ * custom CPUID. Proceed with whatever the kernel found since these features
+ * aren't virtualizable (SME/SEV also require CPUIDs higher than 0x80000008).
+ */
+ return boot_cpu_data.x86_phys_bits;
}
static void kvm_mmu_reset_all_pte_masks(void)
The patch below does not apply to the 4.9-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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From e30a7d623dccdb3f880fbcad980b0cb589a1da45 Mon Sep 17 00:00:00 2001
From: Sean Christopherson <sean.j.christopherson(a)intel.com>
Date: Tue, 7 Jan 2020 16:12:10 -0800
Subject: [PATCH] KVM: x86/mmu: Apply max PA check for MMIO sptes to 32-bit KVM
Remove the bogus 64-bit only condition from the check that disables MMIO
spte optimization when the system supports the max PA, i.e. doesn't have
any reserved PA bits. 32-bit KVM always uses PAE paging for the shadow
MMU, and per Intel's SDM:
PAE paging translates 32-bit linear addresses to 52-bit physical
addresses.
The kernel's restrictions on max physical addresses are limits on how
much memory the kernel can reasonably use, not what physical addresses
are supported by hardware.
Fixes: ce88decffd17 ("KVM: MMU: mmio page fault support")
Cc: stable(a)vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson(a)intel.com>
Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com>
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 2992ff7b42a7..57e4dbddba72 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -6193,7 +6193,7 @@ static void kvm_set_mmio_spte_mask(void)
* If reserved bit is not supported, clear the present bit to disable
* mmio page fault.
*/
- if (IS_ENABLED(CONFIG_X86_64) && shadow_phys_bits == 52)
+ if (shadow_phys_bits == 52)
mask &= ~1ull;
kvm_mmu_set_mmio_spte_mask(mask, mask, ACC_WRITE_MASK | ACC_USER_MASK);
The patch below does not apply to the 4.4-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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From e30a7d623dccdb3f880fbcad980b0cb589a1da45 Mon Sep 17 00:00:00 2001
From: Sean Christopherson <sean.j.christopherson(a)intel.com>
Date: Tue, 7 Jan 2020 16:12:10 -0800
Subject: [PATCH] KVM: x86/mmu: Apply max PA check for MMIO sptes to 32-bit KVM
Remove the bogus 64-bit only condition from the check that disables MMIO
spte optimization when the system supports the max PA, i.e. doesn't have
any reserved PA bits. 32-bit KVM always uses PAE paging for the shadow
MMU, and per Intel's SDM:
PAE paging translates 32-bit linear addresses to 52-bit physical
addresses.
The kernel's restrictions on max physical addresses are limits on how
much memory the kernel can reasonably use, not what physical addresses
are supported by hardware.
Fixes: ce88decffd17 ("KVM: MMU: mmio page fault support")
Cc: stable(a)vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson(a)intel.com>
Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com>
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 2992ff7b42a7..57e4dbddba72 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -6193,7 +6193,7 @@ static void kvm_set_mmio_spte_mask(void)
* If reserved bit is not supported, clear the present bit to disable
* mmio page fault.
*/
- if (IS_ENABLED(CONFIG_X86_64) && shadow_phys_bits == 52)
+ if (shadow_phys_bits == 52)
mask &= ~1ull;
kvm_mmu_set_mmio_spte_mask(mask, mask, ACC_WRITE_MASK | ACC_USER_MASK);
The patch below does not apply to the 4.14-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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From e30a7d623dccdb3f880fbcad980b0cb589a1da45 Mon Sep 17 00:00:00 2001
From: Sean Christopherson <sean.j.christopherson(a)intel.com>
Date: Tue, 7 Jan 2020 16:12:10 -0800
Subject: [PATCH] KVM: x86/mmu: Apply max PA check for MMIO sptes to 32-bit KVM
Remove the bogus 64-bit only condition from the check that disables MMIO
spte optimization when the system supports the max PA, i.e. doesn't have
any reserved PA bits. 32-bit KVM always uses PAE paging for the shadow
MMU, and per Intel's SDM:
PAE paging translates 32-bit linear addresses to 52-bit physical
addresses.
The kernel's restrictions on max physical addresses are limits on how
much memory the kernel can reasonably use, not what physical addresses
are supported by hardware.
Fixes: ce88decffd17 ("KVM: MMU: mmio page fault support")
Cc: stable(a)vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson(a)intel.com>
Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com>
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 2992ff7b42a7..57e4dbddba72 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -6193,7 +6193,7 @@ static void kvm_set_mmio_spte_mask(void)
* If reserved bit is not supported, clear the present bit to disable
* mmio page fault.
*/
- if (IS_ENABLED(CONFIG_X86_64) && shadow_phys_bits == 52)
+ if (shadow_phys_bits == 52)
mask &= ~1ull;
kvm_mmu_set_mmio_spte_mask(mask, mask, ACC_WRITE_MASK | ACC_USER_MASK);
The patch below does not apply to the 4.19-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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From e30a7d623dccdb3f880fbcad980b0cb589a1da45 Mon Sep 17 00:00:00 2001
From: Sean Christopherson <sean.j.christopherson(a)intel.com>
Date: Tue, 7 Jan 2020 16:12:10 -0800
Subject: [PATCH] KVM: x86/mmu: Apply max PA check for MMIO sptes to 32-bit KVM
Remove the bogus 64-bit only condition from the check that disables MMIO
spte optimization when the system supports the max PA, i.e. doesn't have
any reserved PA bits. 32-bit KVM always uses PAE paging for the shadow
MMU, and per Intel's SDM:
PAE paging translates 32-bit linear addresses to 52-bit physical
addresses.
The kernel's restrictions on max physical addresses are limits on how
much memory the kernel can reasonably use, not what physical addresses
are supported by hardware.
Fixes: ce88decffd17 ("KVM: MMU: mmio page fault support")
Cc: stable(a)vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson(a)intel.com>
Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com>
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 2992ff7b42a7..57e4dbddba72 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -6193,7 +6193,7 @@ static void kvm_set_mmio_spte_mask(void)
* If reserved bit is not supported, clear the present bit to disable
* mmio page fault.
*/
- if (IS_ENABLED(CONFIG_X86_64) && shadow_phys_bits == 52)
+ if (shadow_phys_bits == 52)
mask &= ~1ull;
kvm_mmu_set_mmio_spte_mask(mask, mask, ACC_WRITE_MASK | ACC_USER_MASK);
Hello,
We ran automated tests on a recent commit from this kernel tree:
Kernel repo: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
Commit: e3082a4e02b8 - Linux 5.4.19-rc1
The results of these automated tests are provided below.
Overall result: PASSED
Merge: OK
Compile: OK
Tests: OK
All kernel binaries, config files, and logs are available for download here:
https://artifacts.cki-project.org/pipelines/427936
Please reply to this email if you have any questions about the tests that we
ran or if you have any suggestions on how to make future tests more effective.
,-. ,-.
( C ) ( K ) Continuous
`-',-.`-' Kernel
( I ) Integration
`-'
______________________________________________________________________________
Compile testing
---------------
We compiled the kernel for 3 architectures:
aarch64:
make options: -j30 INSTALL_MOD_STRIP=1 targz-pkg
ppc64le:
make options: -j30 INSTALL_MOD_STRIP=1 targz-pkg
x86_64:
make options: -j30 INSTALL_MOD_STRIP=1 targz-pkg
Hardware testing
----------------
We booted each kernel and ran the following tests:
aarch64:
Host 1:
✅ Boot test
✅ Podman system integration test - as root
✅ Podman system integration test - as user
✅ LTP
✅ Loopdev Sanity
✅ Memory function: memfd_create
✅ AMTU (Abstract Machine Test Utility)
✅ Networking bridge: sanity
✅ Ethernet drivers sanity
✅ Networking MACsec: sanity
✅ Networking socket: fuzz
✅ Networking sctp-auth: sockopts test
✅ Networking: igmp conformance test
✅ Networking route: pmtu
✅ Networking route_func - local
✅ Networking route_func - forward
✅ Networking TCP: keepalive test
✅ Networking UDP: socket
✅ Networking tunnel: geneve basic test
✅ Networking tunnel: gre basic
✅ L2TP basic test
✅ Networking tunnel: vxlan basic
✅ Networking ipsec: basic netns - transport
✅ Networking ipsec: basic netns - tunnel
✅ audit: audit testsuite test
✅ httpd: mod_ssl smoke sanity
✅ tuned: tune-processes-through-perf
✅ ALSA PCM loopback test
✅ ALSA Control (mixer) Userspace Element test
✅ storage: SCSI VPD
✅ trace: ftrace/tracer
🚧 ✅ CIFS Connectathon
🚧 ✅ POSIX pjd-fstest suites
🚧 ✅ jvm test suite
🚧 ✅ Memory function: kaslr
🚧 ✅ LTP: openposix test suite
🚧 ✅ Networking vnic: ipvlan/basic
🚧 ✅ iotop: sanity
🚧 ✅ Usex - version 1.9-29
🚧 ✅ storage: dm/common
Host 2:
✅ Boot test
✅ xfstests - ext4
✅ xfstests - xfs
✅ selinux-policy: serge-testsuite
✅ lvm thinp sanity
✅ storage: software RAID testing
🚧 ✅ Storage blktests
ppc64le:
Host 1:
✅ Boot test
✅ xfstests - ext4
✅ xfstests - xfs
✅ selinux-policy: serge-testsuite
✅ lvm thinp sanity
✅ storage: software RAID testing
🚧 ✅ IPMI driver test
🚧 ✅ IPMItool loop stress test
🚧 ✅ Storage blktests
Host 2:
✅ Boot test
✅ Podman system integration test - as root
✅ Podman system integration test - as user
✅ LTP
✅ Loopdev Sanity
✅ Memory function: memfd_create
✅ AMTU (Abstract Machine Test Utility)
✅ Networking bridge: sanity
✅ Ethernet drivers sanity
✅ Networking MACsec: sanity
✅ Networking socket: fuzz
✅ Networking sctp-auth: sockopts test
✅ Networking route: pmtu
✅ Networking route_func - local
✅ Networking route_func - forward
✅ Networking TCP: keepalive test
✅ Networking UDP: socket
✅ Networking tunnel: geneve basic test
✅ Networking tunnel: gre basic
✅ L2TP basic test
✅ Networking tunnel: vxlan basic
✅ Networking ipsec: basic netns - tunnel
✅ audit: audit testsuite test
✅ httpd: mod_ssl smoke sanity
✅ tuned: tune-processes-through-perf
✅ ALSA PCM loopback test
✅ ALSA Control (mixer) Userspace Element test
✅ trace: ftrace/tracer
🚧 ✅ CIFS Connectathon
🚧 ✅ POSIX pjd-fstest suites
🚧 ✅ jvm test suite
🚧 ✅ Memory function: kaslr
🚧 ✅ LTP: openposix test suite
🚧 ✅ Networking vnic: ipvlan/basic
🚧 ✅ iotop: sanity
🚧 ✅ Usex - version 1.9-29
🚧 ✅ storage: dm/common
x86_64:
Host 1:
✅ Boot test
✅ Storage SAN device stress - mpt3sas driver
Host 2:
✅ Boot test
✅ Storage SAN device stress - megaraid_sas
Host 3:
✅ Boot test
✅ Podman system integration test - as root
✅ Podman system integration test - as user
✅ LTP
✅ Loopdev Sanity
✅ Memory function: memfd_create
✅ AMTU (Abstract Machine Test Utility)
✅ Networking bridge: sanity
✅ Ethernet drivers sanity
✅ Networking MACsec: sanity
✅ Networking socket: fuzz
✅ Networking sctp-auth: sockopts test
✅ Networking: igmp conformance test
✅ Networking route: pmtu
✅ Networking route_func - local
✅ Networking route_func - forward
✅ Networking TCP: keepalive test
✅ Networking UDP: socket
✅ Networking tunnel: geneve basic test
✅ Networking tunnel: gre basic
✅ L2TP basic test
✅ Networking tunnel: vxlan basic
✅ Networking ipsec: basic netns - transport
✅ Networking ipsec: basic netns - tunnel
✅ audit: audit testsuite test
✅ httpd: mod_ssl smoke sanity
✅ tuned: tune-processes-through-perf
✅ pciutils: sanity smoke test
✅ ALSA PCM loopback test
✅ ALSA Control (mixer) Userspace Element test
✅ storage: SCSI VPD
✅ trace: ftrace/tracer
🚧 ✅ CIFS Connectathon
🚧 ✅ POSIX pjd-fstest suites
🚧 ✅ jvm test suite
🚧 ✅ Memory function: kaslr
🚧 ✅ LTP: openposix test suite
🚧 ✅ Networking vnic: ipvlan/basic
🚧 ✅ iotop: sanity
🚧 ✅ Usex - version 1.9-29
🚧 ✅ storage: dm/common
Host 4:
✅ Boot test
✅ xfstests - ext4
✅ xfstests - xfs
✅ selinux-policy: serge-testsuite
✅ lvm thinp sanity
✅ storage: software RAID testing
✅ stress: stress-ng
🚧 ✅ IOMMU boot test
🚧 ✅ IPMI driver test
🚧 ✅ IPMItool loop stress test
🚧 ✅ Storage blktests
Test sources: https://github.com/CKI-project/tests-beaker
💚 Pull requests are welcome for new tests or improvements to existing tests!
Waived tests
------------
If the test run included waived tests, they are marked with 🚧. Such tests are
executed but their results are not taken into account. Tests are waived when
their results are not reliable enough, e.g. when they're just introduced or are
being fixed.
Testing timeout
---------------
We aim to provide a report within reasonable timeframe. Tests that haven't
finished running are marked with ⏱. Reports for non-upstream kernels have
a Beaker recipe linked to next to each host.
The patch below does not apply to the 4.19-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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 42ffb0bf584ae5b6b38f72259af1e0ee417ac77f Mon Sep 17 00:00:00 2001
From: Josef Bacik <josef(a)toxicpanda.com>
Date: Thu, 23 Jan 2020 15:33:02 -0500
Subject: [PATCH] btrfs: flush write bio if we loop in extent_write_cache_pages
There exists a deadlock with range_cyclic that has existed forever. If
we loop around with a bio already built we could deadlock with a writer
who has the page locked that we're attempting to write but is waiting on
a page in our bio to be written out. The task traces are as follows
PID: 1329874 TASK: ffff889ebcdf3800 CPU: 33 COMMAND: "kworker/u113:5"
#0 [ffffc900297bb658] __schedule at ffffffff81a4c33f
#1 [ffffc900297bb6e0] schedule at ffffffff81a4c6e3
#2 [ffffc900297bb6f8] io_schedule at ffffffff81a4ca42
#3 [ffffc900297bb708] __lock_page at ffffffff811f145b
#4 [ffffc900297bb798] __process_pages_contig at ffffffff814bc502
#5 [ffffc900297bb8c8] lock_delalloc_pages at ffffffff814bc684
#6 [ffffc900297bb900] find_lock_delalloc_range at ffffffff814be9ff
#7 [ffffc900297bb9a0] writepage_delalloc at ffffffff814bebd0
#8 [ffffc900297bba18] __extent_writepage at ffffffff814bfbf2
#9 [ffffc900297bba98] extent_write_cache_pages at ffffffff814bffbd
PID: 2167901 TASK: ffff889dc6a59c00 CPU: 14 COMMAND:
"aio-dio-invalid"
#0 [ffffc9003b50bb18] __schedule at ffffffff81a4c33f
#1 [ffffc9003b50bba0] schedule at ffffffff81a4c6e3
#2 [ffffc9003b50bbb8] io_schedule at ffffffff81a4ca42
#3 [ffffc9003b50bbc8] wait_on_page_bit at ffffffff811f24d6
#4 [ffffc9003b50bc60] prepare_pages at ffffffff814b05a7
#5 [ffffc9003b50bcd8] btrfs_buffered_write at ffffffff814b1359
#6 [ffffc9003b50bdb0] btrfs_file_write_iter at ffffffff814b5933
#7 [ffffc9003b50be38] new_sync_write at ffffffff8128f6a8
#8 [ffffc9003b50bec8] vfs_write at ffffffff81292b9d
#9 [ffffc9003b50bf00] ksys_pwrite64 at ffffffff81293032
I used drgn to find the respective pages we were stuck on
page_entry.page 0xffffea00fbfc7500 index 8148 bit 15 pid 2167901
page_entry.page 0xffffea00f9bb7400 index 7680 bit 0 pid 1329874
As you can see the kworker is waiting for bit 0 (PG_locked) on index
7680, and aio-dio-invalid is waiting for bit 15 (PG_writeback) on index
8148. aio-dio-invalid has 7680, and the kworker epd looks like the
following
crash> struct extent_page_data ffffc900297bbbb0
struct extent_page_data {
bio = 0xffff889f747ed830,
tree = 0xffff889eed6ba448,
extent_locked = 0,
sync_io = 0
}
Probably worth mentioning as well that it waits for writeback of the
page to complete while holding a lock on it (at prepare_pages()).
Using drgn I walked the bio pages looking for page
0xffffea00fbfc7500 which is the one we're waiting for writeback on
bio = Object(prog, 'struct bio', address=0xffff889f747ed830)
for i in range(0, bio.bi_vcnt.value_()):
bv = bio.bi_io_vec[i]
if bv.bv_page.value_() == 0xffffea00fbfc7500:
print("FOUND IT")
which validated what I suspected.
The fix for this is simple, flush the epd before we loop back around to
the beginning of the file during writeout.
Fixes: b293f02e1423 ("Btrfs: Add writepages support")
CC: stable(a)vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana(a)suse.com>
Signed-off-by: Josef Bacik <josef(a)toxicpanda.com>
Signed-off-by: David Sterba <dsterba(a)suse.com>
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index e2d30287e2d5..8ff17bc30d5a 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4166,7 +4166,16 @@ static int extent_write_cache_pages(struct address_space *mapping,
*/
scanned = 1;
index = 0;
- goto retry;
+
+ /*
+ * If we're looping we could run into a page that is locked by a
+ * writer and that writer could be waiting on writeback for a
+ * page in our current bio, and thus deadlock, so flush the
+ * write bio here.
+ */
+ ret = flush_write_bio(epd);
+ if (!ret)
+ goto retry;
}
if (wbc->range_cyclic || (wbc->nr_to_write > 0 && range_whole))
The patch below does not apply to the 4.14-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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 42ffb0bf584ae5b6b38f72259af1e0ee417ac77f Mon Sep 17 00:00:00 2001
From: Josef Bacik <josef(a)toxicpanda.com>
Date: Thu, 23 Jan 2020 15:33:02 -0500
Subject: [PATCH] btrfs: flush write bio if we loop in extent_write_cache_pages
There exists a deadlock with range_cyclic that has existed forever. If
we loop around with a bio already built we could deadlock with a writer
who has the page locked that we're attempting to write but is waiting on
a page in our bio to be written out. The task traces are as follows
PID: 1329874 TASK: ffff889ebcdf3800 CPU: 33 COMMAND: "kworker/u113:5"
#0 [ffffc900297bb658] __schedule at ffffffff81a4c33f
#1 [ffffc900297bb6e0] schedule at ffffffff81a4c6e3
#2 [ffffc900297bb6f8] io_schedule at ffffffff81a4ca42
#3 [ffffc900297bb708] __lock_page at ffffffff811f145b
#4 [ffffc900297bb798] __process_pages_contig at ffffffff814bc502
#5 [ffffc900297bb8c8] lock_delalloc_pages at ffffffff814bc684
#6 [ffffc900297bb900] find_lock_delalloc_range at ffffffff814be9ff
#7 [ffffc900297bb9a0] writepage_delalloc at ffffffff814bebd0
#8 [ffffc900297bba18] __extent_writepage at ffffffff814bfbf2
#9 [ffffc900297bba98] extent_write_cache_pages at ffffffff814bffbd
PID: 2167901 TASK: ffff889dc6a59c00 CPU: 14 COMMAND:
"aio-dio-invalid"
#0 [ffffc9003b50bb18] __schedule at ffffffff81a4c33f
#1 [ffffc9003b50bba0] schedule at ffffffff81a4c6e3
#2 [ffffc9003b50bbb8] io_schedule at ffffffff81a4ca42
#3 [ffffc9003b50bbc8] wait_on_page_bit at ffffffff811f24d6
#4 [ffffc9003b50bc60] prepare_pages at ffffffff814b05a7
#5 [ffffc9003b50bcd8] btrfs_buffered_write at ffffffff814b1359
#6 [ffffc9003b50bdb0] btrfs_file_write_iter at ffffffff814b5933
#7 [ffffc9003b50be38] new_sync_write at ffffffff8128f6a8
#8 [ffffc9003b50bec8] vfs_write at ffffffff81292b9d
#9 [ffffc9003b50bf00] ksys_pwrite64 at ffffffff81293032
I used drgn to find the respective pages we were stuck on
page_entry.page 0xffffea00fbfc7500 index 8148 bit 15 pid 2167901
page_entry.page 0xffffea00f9bb7400 index 7680 bit 0 pid 1329874
As you can see the kworker is waiting for bit 0 (PG_locked) on index
7680, and aio-dio-invalid is waiting for bit 15 (PG_writeback) on index
8148. aio-dio-invalid has 7680, and the kworker epd looks like the
following
crash> struct extent_page_data ffffc900297bbbb0
struct extent_page_data {
bio = 0xffff889f747ed830,
tree = 0xffff889eed6ba448,
extent_locked = 0,
sync_io = 0
}
Probably worth mentioning as well that it waits for writeback of the
page to complete while holding a lock on it (at prepare_pages()).
Using drgn I walked the bio pages looking for page
0xffffea00fbfc7500 which is the one we're waiting for writeback on
bio = Object(prog, 'struct bio', address=0xffff889f747ed830)
for i in range(0, bio.bi_vcnt.value_()):
bv = bio.bi_io_vec[i]
if bv.bv_page.value_() == 0xffffea00fbfc7500:
print("FOUND IT")
which validated what I suspected.
The fix for this is simple, flush the epd before we loop back around to
the beginning of the file during writeout.
Fixes: b293f02e1423 ("Btrfs: Add writepages support")
CC: stable(a)vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana(a)suse.com>
Signed-off-by: Josef Bacik <josef(a)toxicpanda.com>
Signed-off-by: David Sterba <dsterba(a)suse.com>
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index e2d30287e2d5..8ff17bc30d5a 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4166,7 +4166,16 @@ static int extent_write_cache_pages(struct address_space *mapping,
*/
scanned = 1;
index = 0;
- goto retry;
+
+ /*
+ * If we're looping we could run into a page that is locked by a
+ * writer and that writer could be waiting on writeback for a
+ * page in our current bio, and thus deadlock, so flush the
+ * write bio here.
+ */
+ ret = flush_write_bio(epd);
+ if (!ret)
+ goto retry;
}
if (wbc->range_cyclic || (wbc->nr_to_write > 0 && range_whole))