| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
fs/netfs/read_collect: add to next->prev_donated
If multiple subrequests donate data to the same "next" request
(depending on the subrequest completion order), each of them would
overwrite the `prev_donated` field, causing data corruption and a
BUG() crash ("Can't donate prior to front"). |
| In the Linux kernel, the following vulnerability has been resolved:
greybus: lights: check return of get_channel_from_mode
If channel for the given node is not found we return null from
get_channel_from_mode. Make sure we validate the return pointer
before using it in two of the missing places.
This was originally reported in [0]:
Found by Linux Verification Center (linuxtesting.org) with SVACE.
[0] https://lore.kernel.org/all/20240301190425.120605-1-m.lobanov@rosalinux.ru |
| In the Linux kernel, the following vulnerability has been resolved:
ALSA: timer: Set lower bound of start tick time
Currently ALSA timer doesn't have the lower limit of the start tick
time, and it allows a very small size, e.g. 1 tick with 1ns resolution
for hrtimer. Such a situation may lead to an unexpected RCU stall,
where the callback repeatedly queuing the expire update, as reported
by fuzzer.
This patch introduces a sanity check of the timer start tick time, so
that the system returns an error when a too small start size is set.
As of this patch, the lower limit is hard-coded to 100us, which is
small enough but can still work somehow. |
| In the Linux kernel, the following vulnerability has been resolved:
crypto: bcm - Fix pointer arithmetic
In spu2_dump_omd() value of ptr is increased by ciph_key_len
instead of hash_iv_len which could lead to going beyond the
buffer boundaries.
Fix this bug by changing ciph_key_len to hash_iv_len.
Found by Linux Verification Center (linuxtesting.org) with SVACE. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: ar5523: enable proper endpoint verification
Syzkaller reports [1] hitting a warning about an endpoint in use
not having an expected type to it.
Fix the issue by checking for the existence of all proper
endpoints with their according types intact.
Sadly, this patch has not been tested on real hardware.
[1] Syzkaller report:
------------[ cut here ]------------
usb 1-1: BOGUS urb xfer, pipe 3 != type 1
WARNING: CPU: 0 PID: 3643 at drivers/usb/core/urb.c:504 usb_submit_urb+0xed6/0x1880 drivers/usb/core/urb.c:504
...
Call Trace:
<TASK>
ar5523_cmd+0x41b/0x780 drivers/net/wireless/ath/ar5523/ar5523.c:275
ar5523_cmd_read drivers/net/wireless/ath/ar5523/ar5523.c:302 [inline]
ar5523_host_available drivers/net/wireless/ath/ar5523/ar5523.c:1376 [inline]
ar5523_probe+0x14b0/0x1d10 drivers/net/wireless/ath/ar5523/ar5523.c:1655
usb_probe_interface+0x30f/0x7f0 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:560 [inline]
really_probe+0x249/0xb90 drivers/base/dd.c:639
__driver_probe_device+0x1df/0x4d0 drivers/base/dd.c:778
driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:808
__device_attach_driver+0x1d4/0x2e0 drivers/base/dd.c:936
bus_for_each_drv+0x163/0x1e0 drivers/base/bus.c:427
__device_attach+0x1e4/0x530 drivers/base/dd.c:1008
bus_probe_device+0x1e8/0x2a0 drivers/base/bus.c:487
device_add+0xbd9/0x1e90 drivers/base/core.c:3517
usb_set_configuration+0x101d/0x1900 drivers/usb/core/message.c:2170
usb_generic_driver_probe+0xbe/0x100 drivers/usb/core/generic.c:238
usb_probe_device+0xd8/0x2c0 drivers/usb/core/driver.c:293
call_driver_probe drivers/base/dd.c:560 [inline]
really_probe+0x249/0xb90 drivers/base/dd.c:639
__driver_probe_device+0x1df/0x4d0 drivers/base/dd.c:778
driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:808
__device_attach_driver+0x1d4/0x2e0 drivers/base/dd.c:936
bus_for_each_drv+0x163/0x1e0 drivers/base/bus.c:427
__device_attach+0x1e4/0x530 drivers/base/dd.c:1008
bus_probe_device+0x1e8/0x2a0 drivers/base/bus.c:487
device_add+0xbd9/0x1e90 drivers/base/core.c:3517
usb_new_device.cold+0x685/0x10ad drivers/usb/core/hub.c:2573
hub_port_connect drivers/usb/core/hub.c:5353 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5497 [inline]
port_event drivers/usb/core/hub.c:5653 [inline]
hub_event+0x26cb/0x45d0 drivers/usb/core/hub.c:5735
process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
worker_thread+0x669/0x1090 kernel/workqueue.c:2436
kthread+0x2e8/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK> |
| In the Linux kernel, the following vulnerability has been resolved:
nfc: nci: Fix uninit-value in nci_rx_work
syzbot reported the following uninit-value access issue [1]
nci_rx_work() parses received packet from ndev->rx_q. It should be
validated header size, payload size and total packet size before
processing the packet. If an invalid packet is detected, it should be
silently discarded. |
| In the Linux kernel, the following vulnerability has been resolved:
net/mlx5e: kTLS, Fix incorrect page refcounting
The kTLS tx handling code is using a mix of get_page() and
page_ref_inc() APIs to increment the page reference. But on the release
path (mlx5e_ktls_tx_handle_resync_dump_comp()), only put_page() is used.
This is an issue when using pages from large folios: the get_page()
references are stored on the folio page while the page_ref_inc()
references are stored directly in the given page. On release the folio
page will be dereferenced too many times.
This was found while doing kTLS testing with sendfile() + ZC when the
served file was read from NFS on a kernel with NFS large folios support
(commit 49b29a573da8 ("nfs: add support for large folios")). |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: VMX: Bury Intel PT virtualization (guest/host mode) behind CONFIG_BROKEN
Hide KVM's pt_mode module param behind CONFIG_BROKEN, i.e. disable support
for virtualizing Intel PT via guest/host mode unless BROKEN=y. There are
myriad bugs in the implementation, some of which are fatal to the guest,
and others which put the stability and health of the host at risk.
For guest fatalities, the most glaring issue is that KVM fails to ensure
tracing is disabled, and *stays* disabled prior to VM-Enter, which is
necessary as hardware disallows loading (the guest's) RTIT_CTL if tracing
is enabled (enforced via a VMX consistency check). Per the SDM:
If the logical processor is operating with Intel PT enabled (if
IA32_RTIT_CTL.TraceEn = 1) at the time of VM entry, the "load
IA32_RTIT_CTL" VM-entry control must be 0.
On the host side, KVM doesn't validate the guest CPUID configuration
provided by userspace, and even worse, uses the guest configuration to
decide what MSRs to save/load at VM-Enter and VM-Exit. E.g. configuring
guest CPUID to enumerate more address ranges than are supported in hardware
will result in KVM trying to passthrough, save, and load non-existent MSRs,
which generates a variety of WARNs, ToPA ERRORs in the host, a potential
deadlock, etc. |
| In the Linux kernel, the following vulnerability has been resolved:
mm: resolve faulty mmap_region() error path behaviour
The mmap_region() function is somewhat terrifying, with spaghetti-like
control flow and numerous means by which issues can arise and incomplete
state, memory leaks and other unpleasantness can occur.
A large amount of the complexity arises from trying to handle errors late
in the process of mapping a VMA, which forms the basis of recently
observed issues with resource leaks and observable inconsistent state.
Taking advantage of previous patches in this series we move a number of
checks earlier in the code, simplifying things by moving the core of the
logic into a static internal function __mmap_region().
Doing this allows us to perform a number of checks up front before we do
any real work, and allows us to unwind the writable unmap check
unconditionally as required and to perform a CONFIG_DEBUG_VM_MAPLE_TREE
validation unconditionally also.
We move a number of things here:
1. We preallocate memory for the iterator before we call the file-backed
memory hook, allowing us to exit early and avoid having to perform
complicated and error-prone close/free logic. We carefully free
iterator state on both success and error paths.
2. The enclosing mmap_region() function handles the mapping_map_writable()
logic early. Previously the logic had the mapping_map_writable() at the
point of mapping a newly allocated file-backed VMA, and a matching
mapping_unmap_writable() on success and error paths.
We now do this unconditionally if this is a file-backed, shared writable
mapping. If a driver changes the flags to eliminate VM_MAYWRITE, however
doing so does not invalidate the seal check we just performed, and we in
any case always decrement the counter in the wrapper.
We perform a debug assert to ensure a driver does not attempt to do the
opposite.
3. We also move arch_validate_flags() up into the mmap_region()
function. This is only relevant on arm64 and sparc64, and the check is
only meaningful for SPARC with ADI enabled. We explicitly add a warning
for this arch if a driver invalidates this check, though the code ought
eventually to be fixed to eliminate the need for this.
With all of these measures in place, we no longer need to explicitly close
the VMA on error paths, as we place all checks which might fail prior to a
call to any driver mmap hook.
This eliminates an entire class of errors, makes the code easier to reason
about and more robust. |
| In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: Additional check in ntfs_file_release |
| In the Linux kernel, the following vulnerability has been resolved:
drm/radeon: Fix encoder->possible_clones
Include the encoder itself in its possible_clones bitmask.
In the past nothing validated that drivers were populating
possible_clones correctly, but that changed in commit
74d2aacbe840 ("drm: Validate encoder->possible_clones").
Looks like radeon never got the memo and is still not
following the rules 100% correctly.
This results in some warnings during driver initialization:
Bogus possible_clones: [ENCODER:46:TV-46] possible_clones=0x4 (full encoder mask=0x7)
WARNING: CPU: 0 PID: 170 at drivers/gpu/drm/drm_mode_config.c:615 drm_mode_config_validate+0x113/0x39c
...
(cherry picked from commit 3b6e7d40649c0d75572039aff9d0911864c689db) |
| In the Linux kernel, the following vulnerability has been resolved:
maple_tree: correct tree corruption on spanning store
Patch series "maple_tree: correct tree corruption on spanning store", v3.
There has been a nasty yet subtle maple tree corruption bug that appears
to have been in existence since the inception of the algorithm.
This bug seems far more likely to happen since commit f8d112a4e657
("mm/mmap: avoid zeroing vma tree in mmap_region()"), which is the point
at which reports started to be submitted concerning this bug.
We were made definitely aware of the bug thanks to the kind efforts of
Bert Karwatzki who helped enormously in my being able to track this down
and identify the cause of it.
The bug arises when an attempt is made to perform a spanning store across
two leaf nodes, where the right leaf node is the rightmost child of the
shared parent, AND the store completely consumes the right-mode node.
This results in mas_wr_spanning_store() mitakenly duplicating the new and
existing entries at the maximum pivot within the range, and thus maple
tree corruption.
The fix patch corrects this by detecting this scenario and disallowing the
mistaken duplicate copy.
The fix patch commit message goes into great detail as to how this occurs.
This series also includes a test which reliably reproduces the issue, and
asserts that the fix works correctly.
Bert has kindly tested the fix and confirmed it resolved his issues. Also
Mikhail Gavrilov kindly reported what appears to be precisely the same
bug, which this fix should also resolve.
This patch (of 2):
There has been a subtle bug present in the maple tree implementation from
its inception.
This arises from how stores are performed - when a store occurs, it will
overwrite overlapping ranges and adjust the tree as necessary to
accommodate this.
A range may always ultimately span two leaf nodes. In this instance we
walk the two leaf nodes, determine which elements are not overwritten to
the left and to the right of the start and end of the ranges respectively
and then rebalance the tree to contain these entries and the newly
inserted one.
This kind of store is dubbed a 'spanning store' and is implemented by
mas_wr_spanning_store().
In order to reach this stage, mas_store_gfp() invokes
mas_wr_preallocate(), mas_wr_store_type() and mas_wr_walk() in turn to
walk the tree and update the object (mas) to traverse to the location
where the write should be performed, determining its store type.
When a spanning store is required, this function returns false stopping at
the parent node which contains the target range, and mas_wr_store_type()
marks the mas->store_type as wr_spanning_store to denote this fact.
When we go to perform the store in mas_wr_spanning_store(), we first
determine the elements AFTER the END of the range we wish to store (that
is, to the right of the entry to be inserted) - we do this by walking to
the NEXT pivot in the tree (i.e. r_mas.last + 1), starting at the node we
have just determined contains the range over which we intend to write.
We then turn our attention to the entries to the left of the entry we are
inserting, whose state is represented by l_mas, and copy these into a 'big
node', which is a special node which contains enough slots to contain two
leaf node's worth of data.
We then copy the entry we wish to store immediately after this - the copy
and the insertion of the new entry is performed by mas_store_b_node().
After this we copy the elements to the right of the end of the range which
we are inserting, if we have not exceeded the length of the node (i.e.
r_mas.offset <= r_mas.end).
Herein lies the bug - under very specific circumstances, this logic can
break and corrupt the maple tree.
Consider the following tree:
Height
0 Root Node
/ \
pivot = 0xffff / \ pivot = ULONG_MAX
/
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
ceph: remove the incorrect Fw reference check when dirtying pages
When doing the direct-io reads it will also try to mark pages dirty,
but for the read path it won't hold the Fw caps and there is case
will it get the Fw reference. |
| In the Linux kernel, the following vulnerability has been resolved:
ACPI: PRM: Find EFI_MEMORY_RUNTIME block for PRM handler and context
PRMT needs to find the correct type of block to translate the PA-VA
mapping for EFI runtime services.
The issue arises because the PRMT is finding a block of type
EFI_CONVENTIONAL_MEMORY, which is not appropriate for runtime services
as described in Section 2.2.2 (Runtime Services) of the UEFI
Specification [1]. Since the PRM handler is a type of runtime service,
this causes an exception when the PRM handler is called.
[Firmware Bug]: Unable to handle paging request in EFI runtime service
WARNING: CPU: 22 PID: 4330 at drivers/firmware/efi/runtime-wrappers.c:341
__efi_queue_work+0x11c/0x170
Call trace:
Let PRMT find a block with EFI_MEMORY_RUNTIME for PRM handler and PRM
context.
If no suitable block is found, a warning message will be printed, but
the procedure continues to manage the next PRM handler.
However, if the PRM handler is actually called without proper allocation,
it would result in a failure during error handling.
By using the correct memory types for runtime services, ensure that the
PRM handler and the context are properly mapped in the virtual address
space during runtime, preventing the paging request error.
The issue is really that only memory that has been remapped for runtime
by the firmware can be used by the PRM handler, and so the region needs
to have the EFI_MEMORY_RUNTIME attribute.
[ rjw: Subject and changelog edits ] |
| In the Linux kernel, the following vulnerability has been resolved:
iommu/vt-d: Fix incorrect pci_for_each_dma_alias() for non-PCI devices
Previously, the domain_context_clear() function incorrectly called
pci_for_each_dma_alias() to set up context entries for non-PCI devices.
This could lead to kernel hangs or other unexpected behavior.
Add a check to only call pci_for_each_dma_alias() for PCI devices. For
non-PCI devices, domain_context_clear_one() is called directly. |
| In the Linux kernel, the following vulnerability has been resolved:
kthread: unpark only parked kthread
Calling into kthread unparking unconditionally is mostly harmless when
the kthread is already unparked. The wake up is then simply ignored
because the target is not in TASK_PARKED state.
However if the kthread is per CPU, the wake up is preceded by a call
to kthread_bind() which expects the task to be inactive and in
TASK_PARKED state, which obviously isn't the case if it is unparked.
As a result, calling kthread_stop() on an unparked per-cpu kthread
triggers such a warning:
WARNING: CPU: 0 PID: 11 at kernel/kthread.c:525 __kthread_bind_mask kernel/kthread.c:525
<TASK>
kthread_stop+0x17a/0x630 kernel/kthread.c:707
destroy_workqueue+0x136/0xc40 kernel/workqueue.c:5810
wg_destruct+0x1e2/0x2e0 drivers/net/wireguard/device.c:257
netdev_run_todo+0xe1a/0x1000 net/core/dev.c:10693
default_device_exit_batch+0xa14/0xa90 net/core/dev.c:11769
ops_exit_list net/core/net_namespace.c:178 [inline]
cleanup_net+0x89d/0xcc0 net/core/net_namespace.c:640
process_one_work kernel/workqueue.c:3231 [inline]
process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
worker_thread+0x86d/0xd70 kernel/workqueue.c:3393
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
Fix this with skipping unecessary unparking while stopping a kthread. |
| In the Linux kernel, the following vulnerability has been resolved:
jbd2: stop waiting for space when jbd2_cleanup_journal_tail() returns error
In __jbd2_log_wait_for_space(), we might call jbd2_cleanup_journal_tail()
to recover some journal space. But if an error occurs while executing
jbd2_cleanup_journal_tail() (e.g., an EIO), we don't stop waiting for free
space right away, we try other branches, and if j_committing_transaction
is NULL (i.e., the tid is 0), we will get the following complain:
============================================
JBD2: I/O error when updating journal superblock for sdd-8.
__jbd2_log_wait_for_space: needed 256 blocks and only had 217 space available
__jbd2_log_wait_for_space: no way to get more journal space in sdd-8
------------[ cut here ]------------
WARNING: CPU: 2 PID: 139804 at fs/jbd2/checkpoint.c:109 __jbd2_log_wait_for_space+0x251/0x2e0
Modules linked in:
CPU: 2 PID: 139804 Comm: kworker/u8:3 Not tainted 6.6.0+ #1
RIP: 0010:__jbd2_log_wait_for_space+0x251/0x2e0
Call Trace:
<TASK>
add_transaction_credits+0x5d1/0x5e0
start_this_handle+0x1ef/0x6a0
jbd2__journal_start+0x18b/0x340
ext4_dirty_inode+0x5d/0xb0
__mark_inode_dirty+0xe4/0x5d0
generic_update_time+0x60/0x70
[...]
============================================
So only if jbd2_cleanup_journal_tail() returns 1, i.e., there is nothing to
clean up at the moment, continue to try to reclaim free space in other ways.
Note that this fix relies on commit 6f6a6fda2945 ("jbd2: fix ocfs2 corrupt
when updating journal superblock fails") to make jbd2_cleanup_journal_tail
return the correct error code. |
| In the Linux kernel, the following vulnerability has been resolved:
ACPI: PAD: fix crash in exit_round_robin()
The kernel occasionally crashes in cpumask_clear_cpu(), which is called
within exit_round_robin(), because when executing clear_bit(nr, addr) with
nr set to 0xffffffff, the address calculation may cause misalignment within
the memory, leading to access to an invalid memory address.
----------
BUG: unable to handle kernel paging request at ffffffffe0740618
...
CPU: 3 PID: 2919323 Comm: acpi_pad/14 Kdump: loaded Tainted: G OE X --------- - - 4.18.0-425.19.2.el8_7.x86_64 #1
...
RIP: 0010:power_saving_thread+0x313/0x411 [acpi_pad]
Code: 89 cd 48 89 d3 eb d1 48 c7 c7 55 70 72 c0 e8 64 86 b0 e4 c6 05 0d a1 02 00 01 e9 bc fd ff ff 45 89 e4 42 8b 04 a5 20 82 72 c0 <f0> 48 0f b3 05 f4 9c 01 00 42 c7 04 a5 20 82 72 c0 ff ff ff ff 31
RSP: 0018:ff72a5d51fa77ec8 EFLAGS: 00010202
RAX: 00000000ffffffff RBX: ff462981e5d8cb80 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000246 RDI: 0000000000000246
RBP: ff46297556959d80 R08: 0000000000000382 R09: ff46297c8d0f38d8
R10: 0000000000000000 R11: 0000000000000001 R12: 000000000000000e
R13: 0000000000000000 R14: ffffffffffffffff R15: 000000000000000e
FS: 0000000000000000(0000) GS:ff46297a800c0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffe0740618 CR3: 0000007e20410004 CR4: 0000000000771ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
? acpi_pad_add+0x120/0x120 [acpi_pad]
kthread+0x10b/0x130
? set_kthread_struct+0x50/0x50
ret_from_fork+0x1f/0x40
...
CR2: ffffffffe0740618
crash> dis -lr ffffffffc0726923
...
/usr/src/debug/kernel-4.18.0-425.19.2.el8_7/linux-4.18.0-425.19.2.el8_7.x86_64/./include/linux/cpumask.h: 114
0xffffffffc0726918 <power_saving_thread+776>: mov %r12d,%r12d
/usr/src/debug/kernel-4.18.0-425.19.2.el8_7/linux-4.18.0-425.19.2.el8_7.x86_64/./include/linux/cpumask.h: 325
0xffffffffc072691b <power_saving_thread+779>: mov -0x3f8d7de0(,%r12,4),%eax
/usr/src/debug/kernel-4.18.0-425.19.2.el8_7/linux-4.18.0-425.19.2.el8_7.x86_64/./arch/x86/include/asm/bitops.h: 80
0xffffffffc0726923 <power_saving_thread+787>: lock btr %rax,0x19cf4(%rip) # 0xffffffffc0740620 <pad_busy_cpus_bits>
crash> px tsk_in_cpu[14]
$66 = 0xffffffff
crash> px 0xffffffffc072692c+0x19cf4
$99 = 0xffffffffc0740620
crash> sym 0xffffffffc0740620
ffffffffc0740620 (b) pad_busy_cpus_bits [acpi_pad]
crash> px pad_busy_cpus_bits[0]
$42 = 0xfffc0
----------
To fix this, ensure that tsk_in_cpu[tsk_index] != -1 before calling
cpumask_clear_cpu() in exit_round_robin(), just as it is done in
round_robin_cpu().
[ rjw: Subject edit, avoid updates to the same value ] |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: mvm: pause TCM when the firmware is stopped
Not doing so will make us send a host command to the transport while the
firmware is not alive, which will trigger a WARNING.
bad state = 0
WARNING: CPU: 2 PID: 17434 at drivers/net/wireless/intel/iwlwifi/iwl-trans.c:115 iwl_trans_send_cmd+0x1cb/0x1e0 [iwlwifi]
RIP: 0010:iwl_trans_send_cmd+0x1cb/0x1e0 [iwlwifi]
Call Trace:
<TASK>
iwl_mvm_send_cmd+0x40/0xc0 [iwlmvm]
iwl_mvm_config_scan+0x198/0x260 [iwlmvm]
iwl_mvm_recalc_tcm+0x730/0x11d0 [iwlmvm]
iwl_mvm_tcm_work+0x1d/0x30 [iwlmvm]
process_one_work+0x29e/0x640
worker_thread+0x2df/0x690
? rescuer_thread+0x540/0x540
kthread+0x192/0x1e0
? set_kthread_struct+0x90/0x90
ret_from_fork+0x22/0x30 |
| In the Linux kernel, the following vulnerability has been resolved:
net/mlx5e: SHAMPO, Fix incorrect page release
Under the following conditions:
1) No skb created yet
2) header_size == 0 (no SHAMPO header)
3) header_index + 1 % MLX5E_SHAMPO_WQ_HEADER_PER_PAGE == 0 (this is the
last page fragment of a SHAMPO header page)
a new skb is formed with a page that is NOT a SHAMPO header page (it
is a regular data page). Further down in the same function
(mlx5e_handle_rx_cqe_mpwrq_shampo()), a SHAMPO header page from
header_index is released. This is wrong and it leads to SHAMPO header
pages being released more than once. |