| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
io_uring/net: don't overconsume buffers when using MSG_TRUNC
When a recv/recvmsg is issued with MSG_TRUNC and the incoming packet is
larger than the provided buffer, the net layer returns the full length
of the packet rather than the number of bytes actually copied into the
buffer. As a result, io_uring advances more of the provided buffer ring
than was actually filled. Use the actual filled region size to consume
the buffer, but still return the full size to preserve MSG_TRUNC
semantics.
Take care with multishot, because that seems to already truncate the
consumption based on the available payload size.
This was reported in https://github.com/axboe/liburing/issues/1619.
[axboe: fold in size_t unsigned fix] |
| In the Linux kernel, the following vulnerability has been resolved:
f2fs: accurately adjust free_sections during free_segment_range
In free_segment_range(), MAIN_SECS(sbi) is temporarily reduced by `secs`
to restrict block allocation to the safe remaining main area while valid
blocks in the truncated range are evacuated by GC.
However, FREE_I(sbi)->free_sections tracks the total number of free
sections across the whole filesystem. If any sections within the
truncated range were already free upon entering free_segment_range(),
failing to deduct them from free_sections causes the filesystem to
overestimate available free sections in the active, reduced main area.
This leads to inconsistent free section accounting during GC data
migration and can trigger unexpected allocation failures or assertion
errors when space is tight.
Fix this by calculating the number of already-free sections in the
truncated range, deducting them from free_sections upon entering
free_segment_range(), and restoring them on exit. |
| In the Linux kernel, the following vulnerability has been resolved:
net/sched: cls_u32: fix duplicate handle when node ID pool is exhausted
gen_new_kid() falls back to returning max (htid | 0xFFF) when both
idr_alloc_u32() ranges are full, instead of reporting an error.
u32_change() trusts that value and inserts a new knode with a handle
that is already live in the hash table, breaking handle uniqueness
within the table's node ID space.
The handle was never reserved in ht->handle_idr, so every later error
path that does idr_remove(&ht->handle_idr, handle) removes the
reservation of a different, live knode, which is then reused — one
failed add compounds into further duplicates.
The 4095 limit is per (table, bucket) — ht->handle_idr is per hash
table and the range is derived from htid (bucketid), so a table with
divisor 256 can legitimately hold 256*4095 knodes.
The sibling helper gen_new_htid() has the same silent in-band failure:
it returns 0 when the tp_c handle pool (1..0x7FF) is full, and
u32_init() publishes the root hash table with handle 0 without
checking. Two root tables with handle 0 alias in u32_lookup_ht(),
allowing cross-tcf_proto knode add/lookup/delete. Add the same
exhaustion check that the divisor path already has.
Return an error so u32_change() fails with ENOSPC/ENOMEM when the
node ID space is exhausted, and so u32_init() fails with -ENOMEM
when the hash table ID space is exhausted. The extack message
distinguishes pool exhaustion (-ENOSPC) from a transient allocation
failure (-ENOMEM).
Conditions to recreate the bug:
- CONFIG_NET_SCHED=y, CONFIG_CLS_U32=y (or =m with module loaded)
- Create a clsact qdisc on a device, then add 4095 u32 filters with
auto-generated handles to fill the node ID space for the root hash
table (single bucket). The 4096th auto-handle filter add triggers
the duplicate handle (fh 800::fff reused). Reachable at Level 2
(unshare -Urn, namespace-local CAP_NET_ADMIN).
- For gen_new_htid: create 2047 u32 proto entries on the same block
to fill the tp_c handle pool, then create one more. The root table
gets handle 0 and aliases with other handle-0 root tables. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/pagemap: Prevent double migration of device pages
A device-private folio migrated to system memory by a CPU fault can
remain reachable through the raw-PFN eviction path until migration
finalization drops the source reference.
If eviction selects the same device-private folio during this window,
it can attempt to migrate the folio again. The second migration can leave
an uncharged folio on an LRU list, causing folio_lruvec_lock_irqsave() to
retry indefinitely and resulting in a soft lockup and RCU stall.
Mark successfully migrated device-private folios using a low bit of
their zone_device_data before migration finalization. Make both CPU-fault
and raw-PFN migration paths skip device-private folios carrying this
flag.
Mask the flag when retrieving the drm_pagemap_zdd pointer and preserve
it when a device-private folio is split. Keeping the state on the physical
folio also avoids depending on a virtual address that may change before a
fault occurs.
v2:
- Replace the retired-PFN XArray with an embedded bitmap. (Matthew Brost)
- Mark every base page covered by a migrated folio so retirement remains
valid if the folio is later split.
v3:
- Store the migrated state in a low bit of zone_device_data instead of
adding virtual-range and bitmap tracking to the ZDD. (Matthew Brost)
- Mask the flag when retrieving the ZDD and preserve it when splitting
a folio.
- Drop the pre-existing fixes already covered by Matthew Brost's series:
https://patchwork.freedesktop.org/series/171651/
v4:
- Advance by the folio size only for migration entries marked with
MIGRATE_PFN_COMPOUND. (Sashiko)
v5:
- Simplify ZDD flag updates and folio iteration. (Matthew Brost)
- Skip retired device-private folios in the CPU-fault path. (Matthew Brost)
- Preserve flag bits while taking a new ZDD reference for split folios.
v6:
- Restore MIGRATE_PFN_COMPOUND-aware stepping so non-compound migration
entries are processed one at a time. (Sashiko)
- Drop the pre-existing fixes already covered by Matthew Brost's series:
https://patchwork.freedesktop.org/series/171651/
The lockup was observed as:
[10109.860465] watchdog: BUG: soft lockup - CPU#9 stuck for 26s! [kworker/u65:5:6557]
[10109.860524] Tainted: [S]=CPU_OUT_OF_SPEC, [O]=OOT_MODULE
[10109.860524] Hardware name: ASUS System Product Name/PRIME Z790-P WIFI, BIOS 0812 02/24/2023
[10109.860525] Workqueue: xe_page_fault_work_queue xe_pagefault_queue_work [xe]
[10109.860644] RIP: 0010:_raw_spin_unlock_irqrestore+0x57/0x80
[10109.860655] Call Trace:
[10109.860655] <TASK>
[10109.860657] folio_lruvec_lock_irqsave+0x216/0x220
[10109.860661] ? __pfx_lru_add+0x10/0x10
[10109.860665] folio_batch_move_lru+0xc8/0x450
[10109.860670] ? lock_acquire+0xc4/0x2d0
[10109.860674] ? __folio_batch_add_and_move+0x60/0x2e0
[10109.860677] ? folio_migrate_mapping+0xa6/0x110
[10109.860679] ? folio_migrate_flags+0x13b/0x1b0
[10109.860681] ? __pfx_lru_add+0x10/0x10
[10109.860683] __folio_batch_add_and_move+0xe7/0x2e0
[10109.860685] ? dma_iova_try_alloc+0xb0/0x140
[10109.860689] folio_add_lru+0x64/0x80
[10109.860691] __migrate_device_finalize+0x12c/0x270
[10109.860695] migrate_device_finalize+0x10/0x20
[10109.860698] drm_pagemap_evict_to_ram+0x185/0x370 [drm_gpusvm_helper]
[10109.860704] ? drm_pagemap_evict_to_ram+0x96/0x370 [drm_gpusvm_helper]
[10109.860709] xe_svm_bo_evict+0x15/0x20 [xe]
[10109.860819] ? xe_svm_bo_evict+0x15/0x20 [xe]
[10109.860921] xe_bo_move+0x107e/0x1570 [xe]
[10109.860992] ? xe_ttm_tt_create+0x168/0x340 [xe]
[10109.861059] ? __up_read+0x98/0x2b0
[10109.861061] ? lock_is_held_type+0xa3/0x130
[10109.861067] ttm_bo_handle_move_mem+0xe8/0x1e0 [ttm]
[10109.861075] ttm_bo_evict+0x141/0x1c0 [ttm]
[10109.861081] ttm_bo_evict_cb+0x9f/0x100 [ttm]
[10109.861086] ttm_lru_walk_for_evict+0x84/0x190 [ttm]
[10109.861091] ? xe_ttm_vram_mgr_new+0x258/0x3a0 [xe]
[10109.861198] ttm_bo_alloc_resource+0x219/0
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
ntfs: do not mark the volume clean in sync_fs when errors were recorded
ntfs_put_super() and the remount-read-only path both clear the dirty bit
only when NVolErrors(vol) is false. ntfs_sync_fs() clears it
unconditionally, so any sync() on a volume that recorded an error marks
that volume clean. A volume without this set is then seen as not needing
recovery and it does not run one, so whatever went wrong is never repaired.
This change skips resetting the dirty bit when there are volume errors.
Reproduced on a volume whose $MFTMirr does not match $MFT, which sets the
error flag while leaving the mount read-write: after a write and a sync,
the on-disk volume flags read 0x0000 with this driver and 0x0001 with the
guard in place. |
| In the Linux kernel, the following vulnerability has been resolved:
ntfs: only count successfully cleared runs when freeing clusters
ntfs_cluster_free_from_rl_nolock() adds a run's length to nr_freed
whenever the error bookkeeping condition is false, which includes
cases where ntfs_bitmap_clear_run() actually failed - e.g. a second
run failing with the same errno as an earlier one, or any failure
after a non-ENOMEM error was already recorded. Since a failed
ntfs_bitmap_clear_run() rolls back its partial modifications, no
bits were cleared for that run, yet its length still inflates
vol->free_clusters, corrupting statfs output and the allocator's
free space gate.
Only count runs whose bitmap clear succeeded. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/hugetlb: initialize gigantic bootmem hugepage struct pages earlier
Gigantic bootmem HugeTLB pages are currently initialized from
hugetlb_init(), but page_alloc_init_late() runs earlier and walks
pageblocks to determine zone contiguity.
If a bootmem HugeTLB region is marked noinit, set_zone_contiguous() can
observe still-uninitialized struct pages through
__pageblock_pfn_to_page(). This may not trigger an immediate failure, but
it can make set_zone_contiguous() compute the wrong zone contiguity state.
If extra poisoned-page checks are added in this path, such as
PF_POISONED_CHECK() in page_zone_id(), it can also trigger an early boot
panic.
Initialize gigantic bootmem HugeTLB struct pages from
page_alloc_init_late(), before zone contiguity is evaluated, so later page
allocator setup only sees valid struct page state. This also makes the
initialization order more natural, as struct pages should be initialized
before later code inspects them. |
| In the Linux kernel, the following vulnerability has been resolved:
arm64: entry: Avoid unnecessary local_irq_disable() on kernel exit
Currently, when exiting to kernel mode, we attempt involuntary
preemption. The preemption logic expects IRQs to be disabled, which is
why we call local_irq_disable() before attempting preemption.
However, depending on the context, local_irq_disable() may be
unnecessary:
- __el1_irq(), the non-NMI EL1 IRQ path, already has IRQs disabled, so
local_irq_disable() is redundant.
- irqentry_exit_to_kernel_mode_preempt() immediately returns when
exiting from an NMI-like context, so calling local_irq_disable()
beforehand is unnecessary work.
Furthermore, it confuses the pNMI state tracking when we are in a
context with interrupts disabled and the GIC_PRIO_PSR_I_SET bit is set
in the PMR, leading to a warning when
CONFIG_ARM64_DEBUG_PRIORITY_MASKING=y:
WARNING: ./arch/arm64/include/asm/irqflags.h:63 at arm64_exit_to_kernel_mode+0xb8/0xc0, CPU#40: retsnoop/31805
CPU: 40 UID: 0 PID: 31805 Comm: retsnoop Not tainted 7.2.0-rc6-next-20260805 #7 PREEMPTLAZY
pstate: 234013c9 (nzCv DAIF +PAN -UAO +TCO +DIT +SSBS BTYPE=--)
pc : arm64_exit_to_kernel_mode (arch/arm64/kernel/entry-common.c:63)
lr : el1_abort (arch/arm64/kernel/entry-common.c:323)
pmr: 000000f0
Call trace:
arm64_exit_to_kernel_mode (arch/arm64/kernel/entry-common.c:63) (P)
el1_abort (arch/arm64/kernel/entry-common.c:323)
el1h_64_sync_handler (arch/arm64/kernel/entry-common.c:449)
el1h_64_sync (arch/arm64/kernel/entry.S:589)
[...]
Split arm64_exit_to_kernel_mode() into preempt, non-preempt, and
dispatch parts so that we can avoid this extra work where it is not
needed and avoid breaking the pNMI tracking logic. |
| In the Linux kernel, the following vulnerability has been resolved:
ntfs: leave HasEA flag untouched on setxattr failure
In ntfs_set_ea(), the exit path unconditionally updates the HasEA
flag based on ea_info_qsize. When an error occurs before
ea_info_qsize is updated, NInoClearHasEA() hides existing on-disk
EAs until the inode is evicted.
Only update the flag on success. |
| In the Linux kernel, the following vulnerability has been resolved:
nfsd: initialize DRC hash table before registering shrinker
shrinker_register() precedes the INIT_LIST_HEAD loop and the
drc_hashsize store. On weakly-ordered architectures (arm64, ppc),
a shrinker scan can observe drc_hashsize before the bucket list
heads are initialized, causing a NULL deref in the DRC shrinker
callback.
Move bucket initialization and the drc_hashsize store before
shrinker_register() so the hash table is fully initialized before
it becomes visible to the shrinker. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/madvise: skip device-private PMDs in cold and pageout walks
madvise_cold_or_pageout_pte_range() takes pmd_trans_huge_lock(), whose
pmd_is_huge() check returns true for a device-private PMD. The subsequent
!pmd_present() branch has a VM_BUG_ON() asserting migration is the only
allowed non-present case; a device-private PMD trips it.
Skip device-private PMDs in that non-present branch and continue to
huge_unlock before calling pmd_folio(). Downgrade the check to
VM_WARN_ON_ONCE() so an unexpected PMD softleaf logs a warning rather than
panicking. Drop the thp_migration_supported() guard: it expands to
IS_ENABLED(CONFIG_ARCH_SUPPORTS_PMD_SOFTLEAF), and both
pmd_is_migration_entry() and pmd_is_device_private_entry() already return
false when that config is not selected, so the guard suppresses only the
case where the warning would already be silent.
Potential trigger: an HMM-based GPU driver races with
madvise(MADV_COLD)/MADV_PAGEOUT: pmd_trans_huge(*pmd) reads true, then
migrate_vma_pages() flips the PMD to a device-private entry before the PMD
lock is acquired. |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: qla2xxx: Fix response queue over-consumption in __qla_consume_iocb()
qla24xx_process_response_queue() advances ring_ptr past the head IOCB
before dispatching, so by the time __qla_consume_iocb() runs, ring_ptr
already points at the first continuation IOCB. The function however
looped purex->entry_count times starting at ring_ptr. As entry_count
includes the head, this consumed one entry too many: it stamped
RESPONSE_PROCESSED on the next, unrelated IOCB and advanced the ring
past it, silently dropping a legitimate firmware response. The head
IOCB's signature was also never marked.
Mark the head processed and account for it, then consume only the
entry_count - 1 continuation IOCBs, matching __qla_copy_purex_to_buffer(). |
| In the Linux kernel, the following vulnerability has been resolved:
arm64: hibernate: mask DAIF before restoring hibernated kernel
The arm64 hibernate code manages the exception masking in an unsound
way, leading to potential crashes and/or warnings during resume.
When a hibernation image is saved in `swsusp_arch_suspend()`, all DAIF
exceptions are masked (by virtue of `local_daif_save()`), and the
suspended image is saved assuming that all DAIF exceptions will remain
masked when the image is restored.
When a hibernation image is resumed by `swsusp_arch_resume()`, only
interrupts are masked (by virtue of `local_irq_disable()` in
`resume_target_kernel()`). When pseudo-NMI is enabled the DAIF.IF bits
will be clear, and regardless of pseudo-NMI the DAIF.DA bits will be
clear.
This means that there are two problems:
(1) It is possible to take Debug, SError, or pseudo-NMI exceptions
during the resume process. This is unsafe, as during the resume
process both the old ane new kernels will tranisently be in an
inconsistent state, and swsusp_arch_suspend_exit() won't retain
an executable mapping of any exception vectors.
Any exception taken here will be fatal and silent.
(2) When re-entering the resumed kernel, some DAIF bits will be clear
unexpectedly. This permits Debug, SError, or pseudo-NMI exceptions
to be taken for a short period while the resumed kernel is not yet
in a consistent state.
This is detected by CONFIG_ARM64_DEBUG_PRIORITY_MASKING.
Avoid these issues by masking all DAIF exceptions during resume. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: ath11k: cap out-of-range rx MCS instead of leaving bogus rate
ath11k can receive HT/VHT/HE frames whose reported MCS is above the
maximum that can be expressed in the corresponding mac80211 rate space
(e.g. an HE frame reported with MCS 12, while HE tops out at MCS 11).
The frame itself is valid and decodes correctly, but for such a frame
ath11k_dp_rx_h_rate() leaves rx_status->rate_idx set to the out-of-range
value and never assigns rx_status->encoding, so it stays RX_ENC_LEGACY
from the ath11k_dp_rx_h_ppdu() initialization. Once that frame reaches
mac80211 it trips the rate sanity check and the frame is dropped with a
splat:
ath11k_pci 0000:03:00.0: Received with invalid mcs in HE mode 12
WARNING: CPU: 0 PID: 0 at net/mac80211/rx.c:5433 ieee80211_rx_list+0xb0a/0xe90 [mac80211]
Dropping the frame would discard otherwise valid data, so instead cap the
reported MCS to the maximum the rate space can express and deliver the
frame. Set rx_status->encoding before the range check and assign rate_idx
from the capped value, so a frame with an out-of-range MCS no longer
leaves partial or bogus rate metadata behind. Also downgrade the logging
level since they are not treated as invalid frames now. The only loss is
that such a frame is reported as the capped MCS in the rx rate statistics.
Tested-on: WCN6855 hw2.1 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.41 |
| In the Linux kernel, the following vulnerability has been resolved:
staging: media: tegra-video: fix of_node_put() on VIP parse errors
tegra_vip_channel_of_parse() initializes np from dev->of_node without
taking a reference, but its error paths drop one through the
err_node_put label. This underflows the refcount of the VIP device's
OF node when endpoint parsing fails on a malformed device tree.
The only reference the function takes on np is the success-path
of_node_get() stored in vip->chan.of_node, and that one is already
released by the tegra_vip_init() error path and by tegra_vip_exit().
Return errors directly instead of jumping to the bogus cleanup label. |
| In the Linux kernel, the following vulnerability has been resolved:
svcrdma: Reject Write/Reply chunks with segcount 0
A peer can send a Write or Reply chunk whose segcount field is zero.
xdr_check_write_chunk() only rejects segcount > rc_maxpages, so zero
passes the range check, and xdr_inline_decode(stream, 0) returns the
current (non-NULL) cursor without advancing. The function returns
true and pcl_alloc_write() then links a struct svc_rdma_chunk with
ch_segcount == 0 onto rc_write_pcl or rc_reply_pcl.
An earlier patch in this series made pcl_for_each_segment() safe for
ch_segcount == 0, so this no longer drives the memory walk it used
to. Rejecting the malformed frame at the decode boundary is still
worthwhile as defense in depth: it keeps degenerate zero-segment
chunks off the parsed chunk lists entirely, so any future consumer
that walks ch_segments directly cannot observe one, and it makes the
zero-floor easy to backport to trees where the macro change is more
intrusive. RFC 8166 has no meaning for a Write/Reply chunk that
describes no remote buffer, so no legitimate client is affected.
xdr_check_reply_chunk() funnels Reply chunks through
xdr_check_write_chunk() and inherits the same rejection.
pcl_alloc_write() also links each chunk onto the parsed chunk list
before filling its segment array. If a future change weakens the
segcount-0 rejection, an incomplete chunk is visible to consumers
during the fill loop. Reorder so that list_add_tail() follows the
segment fill loop, ensuring only fully-populated chunks appear on
the list. |
| In the Linux kernel, the following vulnerability has been resolved:
gfs2: move quota_init qc iterator increment
Move qc++ from the loop body into the for-loop increment
expression in gfs2_quota_init().
This keeps iterator progression explicit and avoids mixing pointer
advance with duplicate-slot handling in the loop body. |
| In the Linux kernel, the following vulnerability has been resolved:
block: handle nogenerate/noverify properly in fs-integrity
Check the BIP_CHECK flags before generating or verifying PI information,
otherwise this can be incorrectly called for non-PI metadata and
cause generation of incorrect metadata and crashed in the verification
handler.
The new behavior matches that of the block layer auto-generated
metadata. |
| In the Linux kernel, the following vulnerability has been resolved:
powerpc/irq: Fix missing r2 clobber in PCREL inline assembly
In CONFIG_PPC_KERNEL_PCREL mode, r2 is no longer reserved for the TOC
pointer and is available as a caller-saved register [0].
Both call_do_irq() and call_do_softirq() use inline assembly to call
functions with stack switching, but fail to list r2 in their clobber
lists. This causes the compiler to assume r2 is preserved across these
calls, leading to register corruption when the called functions
(__do_irq and __do_softirq) clobber r2.
As a result of this kernel crash during interrupt handling is seen and
the kernel fails to boot:
BUG: Unable to handle kernel data access on write at 0xc000000404697638
Faulting instruction address: 0xc0000000000181ec
Oops: Kernel access of bad area, sig: 11 [#1]
NIP [c0000000000181ec] __do_IRQ+0x6c/0xc0
With older GCC, the compiler would conservatively allocate
callee-saved registers (like r31) for values spanning function calls,
accidentally avoiding the bug:
<__do_IRQ>:
00 00 00 60 nop
a6 02 08 7c mflr r0
f8 ff e1 fb std r31,-8(r1)
f0 ff c1 fb std r30,-16(r1)
2d 03 10 06 pla r31,53297316
...
3d e8 ff 4b bl c0000000000165ac <__do_irq>
00 00 21 e8 ld r1,0(r1)
28 00 4d e9 ld r10,40(r13)
40 00 21 38 addi r1,r1,64
2a f9 aa 7f stdx r29,r10,r31
With newer GCC 14, the compiler uses r2 for such values, exposing the
missing clobber specification:
<__do_IRQ>:
00 00 00 60 nop
a6 02 08 7c mflr r0
f0 ff c1 fb std r30,-16(r1)
f8 ff e1 fb std r31,-8(r1)
29 02 10 06 pla r2,36252592 # c0000000022aadc0 <__irq_regs>
...
85 dc ff 4b bl c000000000015ee0 <__do_irq>
00 00 21 e8 ld r1,0(r1)
28 00 2d e9 ld r9,40(r13)
30 00 21 38 addi r1,r1,48
2a 11 c9 7f stdx r30,r9,r2
Fix this by adding r2 to the clobber list for both call_do_irq() and
call_do_softirq() when CONFIG_PPC_KERNEL_PCREL is enabled.
[0]: https://www.mail-archive.com/gcc-patches@gcc.gnu.org/msg313226.html |
| In the Linux kernel, the following vulnerability has been resolved:
perf/x86/intel/pt: Fix stop/start with no update
If pt_event_stop() is called without PERF_EF_UPDATE flag, then
perf_aux_output_end() is not called. A subsequent call to pt_event_start()
will call perf_aux_output_begin() again which violates the rule against
nesting and triggers a WARNING in perf_aux_output_begin().
Originally, pt_event_stop() was never called without PERF_EF_UPDATE,
because the only code paths to do so are from event overflow, and Intel PT
does not do that.
However the introduction of group throttling by commit 9734e25fbf5ae
("perf: Fix the throttle logic for a group") meant that an Intel PT event
could be throttled if it was part of a group. Throttling calls PMU
->stop() / ->start() callbacks without flags.
An example is when AUX area sampling is used. The following commands
hit the issue:
echo 10000 > /proc/sys/kernel/perf_event_max_sample_rate
perf record -F32000 --aux-sample -e '{intel_pt//u,cycles:u}' \
-- bash -c 'for i in `seq 1 100000` ; do true ; done'
Use PERF_HES_UPTODATE to track whether perf_aux_output_begin() and
perf_aux_output_end() are balanced. A cleared PERF_HES_UPTODATE bit
indicates that an AUX output context is still open.
Amend pt_event_start() / pt_event_stop() accordingly so that begin/end
stay balanced:
- In non-snapshot mode, stop() always closes the buffer (the buffer may
have run out of space, and that accounting is done by the update), so
a following start() opens a fresh one as before.
- In snapshot/overwrite mode, stop() without PERF_EF_UPDATE leaves the
buffer open so that pt_event_snapshot_aux() can still copy from it,
and start() then only re-enables tracing instead of calling
perf_aux_output_begin() again.
Note that pt_event_del() calls pt_event_stop() with PERF_EF_UPDATE flag set
(as is required by the documentation), so a final call to
perf_aux_output_end() is assured. |
