Archives generated by the command 'perf archive' have to be unpacked
manually.
Following the addition of option '--all' now there also exist a nested
structure of tars, and after further discussion with Red Hat Global
Support Services, they found a feature correctly unpacking archives of
'perf archive' convenient.
Option '--unpack' of 'perf archive' unpacks archives generated by the
command 'perf archive' as well as archives generated when used with
option '--all'.
The 'perf.data' file is placed in the current directory, while debug
symbols are unpacked in '~/.debug' directory. A tar filename can be
passed as an argument, and if not provided the command tries to find a
viable perf.tar file for unpacking.
Signed-off-by: Veronika Molnarova <vmolnaro@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Link: https://lore.kernel.org/r/20231212165909.14459-2-vmolnaro@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
To pick up fixes that went thru perf-tools for v6.7 and to get in sync
with upstream to check for drift in the copies of headers, etc.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When turning an event with attributes to the format including the PMU we
need to move the "event:attributes" format to "event/attributes/" so
that we can copy the event displayed and use it in the command line,
i.e. in 'perf top' we had:
1K cpu_atom/cycles:P/
11K cpu_core/cycles:P/
If I try to use that on the command line:
# perf top -e cpu_atom/cycles:P/
event syntax error: 'cpu_atom/cycles:P/'
\___ Bad event or PMU
Unable to find PMU or event on a PMU of 'cpu_atom'
Initial error:
event syntax error: 'cpu_atom/cycles:P/'
\___ unknown term 'cycles:P' for pmu
'cpu_atom'
valid terms:
event,pc,edge,offcore_rsp,ldlat,inv,umask,cmask,config,config1,config2,config3,name,period,freq,branch_type,time,call-graph,stack-size,no-inherit,inherit,max-stack,nr,no-overwrite,overwrite ,driver-config,percore,aux-output,aux-sample-size,metric-id,raw,legacy-cache,hardware
Run
'perf list' for a list of valid events
Usage: perf top [<options>]
-e, --event <event> event selector. use 'perf list' to list available events
#
Tested-by: Kan Liang <kan.liang@linux.intel.com>
Cc: Hector Martin <marcan@marcan.st>
Cc: Ian Rogers <irogers@google.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/lkml/ZXxyanyZgWBTOnoK@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull SCSI fixes from James Bottomley:
"Two medium sized fixes, both in drivers.
The UFS one adds parsing of clock info structures, which is required
by some host drivers and the aacraid one reverts the IRQ affinity
mapping patch which has been causing regressions noted in kernel
bugzilla 217599"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: ufs: core: Store min and max clk freq from OPP table
Revert "scsi: aacraid: Reply queue mapping to CPUs based on IRQ affinity"
Pull spi fixes from Mark Brown:
"A few bigger things here, the main one being that there were changes
to the atmel driver in this cycle which made it possible to kill
transfers being used for filesystem I/O which turned out to be very
disruptive, the series of patches here undoes that and hardens things
up further.
There's also a few smaller driver specific changes, the main one being
to revert a change that duplicted delays"
* tag 'spi-fix-v6.7-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
spi: atmel: Fix clock issue when using devices with different polarities
spi: spi-imx: correctly configure burst length when using dma
spi: cadence: revert "Add SPI transfer delays"
spi: atmel: Prevent spi transfers from being killed
spi: atmel: Drop unused defines
spi: atmel: Do not cancel a transfer upon any signal
Pull perf fix from Borislav Petkov:
- Avoid iterating over newly created group leader event's siblings
because there are none, and thus prevent a lockdep splat
* tag 'perf_urgent_for_v6.7_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf: Fix perf_event_validate_size() lockdep splat
Pull btrfs fix from David Sterba:
"One more fix that verifies that the snapshot source is a root, same
check is also done in user space but should be done by the ioctl as
well"
* tag 'for-6.7-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: do not allow non subvolume root targets for snapshot
Pull soundwire fixes from Vinod Koul:
- Null pointer dereference for mult link in core
- AC timing fix in intel driver
* tag 'soundwire-6.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/soundwire:
soundwire: intel_ace2x: fix AC timing setting for ACE2.x
soundwire: stream: fix NULL pointer dereference for multi_link
Pull phy fixes from Vinod Koul:
- register offset fix for TI driver
- mediatek driver minimal supported frequency fix
- negative error code in probe fix for sunplus driver
* tag 'phy-fixes-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/phy/linux-phy:
phy: sunplus: return negative error code in sp_usb_phy_probe
phy: mediatek: mipi: mt8183: fix minimal supported frequency
phy: ti: gmii-sel: Fix register offset when parent is not a syscon node
Pull dmaengine fixes from Vinod Koul:
- SPI PDMA data fix for TI k3-psil drivers
- suspend fix, pointer check, logic for arbitration fix and channel
leak fix in fsl-edma driver
- couple of fixes in idxd driver for GRPCFG descriptions and int_handle
field handling
- single fix for stm32 driver for bitfield overflow
* tag 'dmaengine-fix-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine:
dmaengine: fsl-edma: fix DMA channel leak in eDMAv4
dmaengine: fsl-edma: fix wrong pointer check in fsl_edma3_attach_pd()
dmaengine: idxd: Fix incorrect descriptions for GRPCFG register
dmaengine: idxd: Protect int_handle field in hw descriptor
dmaengine: stm32-dma: avoid bitfield overflow assertion
dmaengine: fsl-edma: Add judgment on enabling round robin arbitration
dmaengine: fsl-edma: Do not suspend and resume the masked dma channel when the system is sleeping
dmaengine: ti: k3-psil-am62a: Fix SPI PDMA data
dmaengine: ti: k3-psil-am62: Fix SPI PDMA data
Pull CXL (Compute Express Link) fixes from Dan Williams:
"A collection of CXL fixes.
The touch outside of drivers/cxl/ is for a helper that allocates
physical address space. Device hotplug tests showed that the driver
failed to utilize (skipped over) valid capacity when allocating a new
memory region. Outside of that, new tests uncovered a small crop of
lockdep reports.
There is also some miscellaneous error path and leak fixups that are
not urgent, but useful to cleanup now.
- Fix alloc_free_mem_region()'s scan for address space, prevent false
negative out-of-space events
- Fix sleeping lock acquisition from CXL trace event (atomic context)
- Fix put_device() like for the new CXL PMU driver
- Fix wrong pointer freed on error path
- Fixup several lockdep reports (missing lock hold) from new
assertion in cxl_num_decoders_committed() and new tests"
* tag 'cxl-fixes-6.7-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl:
cxl/pmu: Ensure put_device on pmu devices
cxl/cdat: Free correct buffer on checksum error
cxl/hdm: Fix dpa translation locking
kernel/resource: Increment by align value in get_free_mem_region()
cxl: Add cxl_num_decoders_committed() usage to cxl_test
cxl/memdev: Hold region_rwsem during inject and clear poison ops
cxl/core: Always hold region_rwsem while reading poison lists
cxl/hdm: Fix a benign lockdep splat
Pull EDAC fix from Borislav Petkov:
- A single fix for the EDAC Versal driver to read out register fields
properly
* tag 'edac_urgent_for_v6.7_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras:
EDAC/versal: Read num_csrows and num_chans using the correct bitfield macro
Pull powerpc fixes from Michael Ellerman:
- Fix a bug where heavy VAS (accelerator) usage could race with
partition migration and prevent the migration from completing.
- Update MAINTAINERS to add Aneesh & Naveen.
Thanks to Haren Myneni.
* tag 'powerpc-6.7-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
MAINTAINERS: powerpc: Add Aneesh & Naveen
powerpc/pseries/vas: Migration suspend waits for no in-progress open windows
Pull clk fixes from Stephen Boyd:
"A handful of clk fixes, mostly in the rockchip clk driver:
- Fix a clk name, clk parent, and a register for a clk gate in the
Rockchip rk3128 clk driver
- Add a PLL frequency on Rockchip rk3568 to fix some display
artifacts
- Fix a kbuild dependency for Qualcomm's SM_CAMCC_8550 symbol so that
it isn't possible to select the associated GCC driver"
* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
clk: rockchip: rk3128: Fix SCLK_SDMMC's clock name
clk: rockchip: rk3128: Fix aclk_peri_src's parent
clk: qcom: Fix SM_CAMCC_8550 dependencies
clk: rockchip: rk3128: Fix HCLK_OTG gate register
clk: rockchip: rk3568: Add PLL rate for 292.5MHz
Pull tracing fixes from Steven Rostedt:
- Fix eventfs to check creating new files for events with names greater
than NAME_MAX. The eventfs lookup needs to check the return result of
simple_lookup().
- Fix the ring buffer to check the proper max data size. Events must be
able to fit on the ring buffer sub-buffer, if it cannot, then it
fails to be written and the logic to add the event is avoided. The
code to check if an event can fit failed to add the possible absolute
timestamp which may make the event not be able to fit. This causes
the ring buffer to go into an infinite loop trying to find a
sub-buffer that would fit the event. Luckily, there's a check that
will bail out if it looped over a 1000 times and it also warns.
The real fix is not to add the absolute timestamp to an event that is
starting at the beginning of a sub-buffer because it uses the
sub-buffer timestamp.
By avoiding the timestamp at the start of the sub-buffer allows
events that pass the first check to always find a sub-buffer that it
can fit on.
- Have large events that do not fit on a trace_seq to print "LINE TOO
BIG" like it does for the trace_pipe instead of what it does now
which is to silently drop the output.
- Fix a memory leak of forgetting to free the spare page that is saved
by a trace instance.
- Update the size of the snapshot buffer when the main buffer is
updated if the snapshot buffer is allocated.
- Fix ring buffer timestamp logic by removing all the places that tried
to put the before_stamp back to the write stamp so that the next
event doesn't add an absolute timestamp. But each of these updates
added a race where by making the two timestamp equal, it was
validating the write_stamp so that it can be incorrectly used for
calculating the delta of an event.
- There's a temp buffer used for printing the event that was using the
event data size for allocation when it needed to use the size of the
entire event (meta-data and payload data)
- For hardening, use "%.*s" for printing the trace_marker output, to
limit the amount that is printed by the size of the event. This was
discovered by development that added a bug that truncated the '\0'
and caused a crash.
- Fix a use-after-free bug in the use of the histogram files when an
instance is being removed.
- Remove a useless update in the rb_try_to_discard of the write_stamp.
The before_stamp was already changed to force the next event to add
an absolute timestamp that the write_stamp is not used. But the
write_stamp is modified again using an unneeded 64-bit cmpxchg.
- Fix several races in the 32-bit implementation of the
rb_time_cmpxchg() that does a 64-bit cmpxchg.
- While looking at fixing the 64-bit cmpxchg, I noticed that because
the ring buffer uses normal cmpxchg, and this can be done in NMI
context, there's some architectures that do not have a working
cmpxchg in NMI context. For these architectures, fail recording
events that happen in NMI context.
* tag 'trace-v6.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
ring-buffer: Do not record in NMI if the arch does not support cmpxchg in NMI
ring-buffer: Have rb_time_cmpxchg() set the msb counter too
ring-buffer: Fix 32-bit rb_time_read() race with rb_time_cmpxchg()
ring-buffer: Fix a race in rb_time_cmpxchg() for 32 bit archs
ring-buffer: Remove useless update to write_stamp in rb_try_to_discard()
ring-buffer: Do not try to put back write_stamp
tracing: Fix uaf issue when open the hist or hist_debug file
tracing: Add size check when printing trace_marker output
ring-buffer: Have saved event hold the entire event
ring-buffer: Do not update before stamp when switching sub-buffers
tracing: Update snapshot buffer on resize if it is allocated
ring-buffer: Fix memory leak of free page
eventfs: Fix events beyond NAME_MAX blocking tasks
tracing: Have large events show up as '[LINE TOO BIG]' instead of nothing
ring-buffer: Fix writing to the buffer with max_data_size
Pull arm64 fixes from Catalin Marinas:
- Arm CMN perf: fix the DTC allocation failure path which can end up
erroneously clearing live counters
- arm64/mm: fix hugetlb handling of the dirty page state leading to a
continuous fault loop in user on hardware without dirty bit
management (DBM). That's caused by the dirty+writeable information
not being properly preserved across a series of mprotect(PROT_NONE),
mprotect(PROT_READ|PROT_WRITE)
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: mm: Always make sw-dirty PTEs hw-dirty in pte_modify
perf/arm-cmn: Fail DTC counter allocation correctly
Pull pci fixes from Bjorn Helgaas:
- Limit Max_Read_Request_Size (MRRS) on some MIPS Loongson systems
because they don't all support MRRS > 256, and firmware doesn't
always initialize it correctly, which meant some PCIe devices didn't
work (Jiaxun Yang)
- Add and use pci_enable_link_state_locked() to prevent potential
deadlocks in vmd and qcom drivers (Johan Hovold)
- Revert recent (v6.5) acpiphp resource assignment changes that fixed
issues with hot-adding devices on a root bus or with large BARs, but
introduced new issues with GPU initialization and hot-adding SCSI
disks in QEMU VMs and (Bjorn Helgaas)
* tag 'pci-v6.7-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci:
Revert "PCI: acpiphp: Reassign resources on bridge if necessary"
PCI/ASPM: Add pci_disable_link_state_locked() lockdep assert
PCI/ASPM: Clean up __pci_disable_link_state() 'sem' parameter
PCI: qcom: Clean up ASPM comment
PCI: qcom: Fix potential deadlock when enabling ASPM
PCI: vmd: Fix potential deadlock when enabling ASPM
PCI/ASPM: Add pci_enable_link_state_locked()
PCI: loongson: Limit MRRS to 256
Our btrfs subvolume snapshot <source> <destination> utility enforces
that <source> is the root of the subvolume, however this isn't enforced
in the kernel. Update the kernel to also enforce this limitation to
avoid problems with other users of this ioctl that don't have the
appropriate checks in place.
Reported-by: Martin Michaelis <code@mgjm.de>
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This code is rarely (never?) enabled by distros, and it hasn't caught
anything in decades. Let's kill off this legacy debug code.
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are multiple ways to grab references to credentials, and the only
protection we have against overflowing it is the memory required to do
so.
With memory sizes only moving in one direction, let's bump the reference
count to 64-bit and move it outside the realm of feasibly overflowing.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts commit 40613da52b and the
subsequent fix to it:
cc22522fd5 ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus")
40613da52b fixed a problem where hot-adding a device with large BARs
failed if the bridge windows programmed by firmware were not large enough.
cc22522fd5 ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources()
only for non-root bus") fixed a problem with 40613da52b: an ACPI hot-add
of a device on a PCI root bus (common in the virt world) or firmware
sending ACPI Bus Check to non-existent Root Ports (e.g., on Dell Inspiron
7352/0W6WV0) caused a NULL pointer dereference and suspend/resume hangs.
Unfortunately the combination of 40613da52b and cc22522fd5 caused other
problems:
- Fiona reported that hot-add of SCSI disks in QEMU virtual machine fails
sometimes.
- Dongli reported a similar problem with hot-add of SCSI disks.
- Jonathan reported a console freeze during boot on bare metal due to an
error in radeon GPU initialization.
Revert both patches to avoid adding these problems. This means we will
again see the problems with hot-adding devices with large BARs and the NULL
pointer dereferences and suspend/resume issues that 40613da52b and
cc22522fd5 were intended to fix.
Fixes: 40613da52b ("PCI: acpiphp: Reassign resources on bridge if necessary")
Fixes: cc22522fd5 ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus")
Reported-by: Fiona Ebner <f.ebner@proxmox.com>
Closes: https://lore.kernel.org/r/9eb669c0-d8f2-431d-a700-6da13053ae54@proxmox.com
Reported-by: Dongli Zhang <dongli.zhang@oracle.com>
Closes: https://lore.kernel.org/r/3c4a446a-b167-11b8-f36f-d3c1b49b42e9@oracle.com
Reported-by: Jonathan Woithe <jwoithe@just42.net>
Closes: https://lore.kernel.org/r/ZXpaNCLiDM+Kv38H@marvin.atrad.com.au
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Igor Mammedov <imammedo@redhat.com>
Cc: <stable@vger.kernel.org>
Pull io_uring fixes from Jens Axboe:
"Just two minor fixes:
- Fix for the io_uring socket option commands using the wrong value
on some archs (Al)
- Tweak to the poll lazy wake enable (me)"
* tag 'io_uring-6.7-2023-12-15' of git://git.kernel.dk/linux:
io_uring/cmd: fix breakage in SOCKET_URING_OP_SIOC* implementation
io_uring/poll: don't enable lazy wake for POLLEXCLUSIVE
Pull misc fixes from Andrew Morton:
"17 hotfixes. 8 are cc:stable and the other 9 pertain to post-6.6
issues"
* tag 'mm-hotfixes-stable-2023-12-15-07-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
mm/mglru: reclaim offlined memcgs harder
mm/mglru: respect min_ttl_ms with memcgs
mm/mglru: try to stop at high watermarks
mm/mglru: fix underprotected page cache
mm/shmem: fix race in shmem_undo_range w/THP
Revert "selftests: error out if kernel header files are not yet built"
crash_core: fix the check for whether crashkernel is from high memory
x86, kexec: fix the wrong ifdeffery CONFIG_KEXEC
sh, kexec: fix the incorrect ifdeffery and dependency of CONFIG_KEXEC
mips, kexec: fix the incorrect ifdeffery and dependency of CONFIG_KEXEC
m68k, kexec: fix the incorrect ifdeffery and build dependency of CONFIG_KEXEC
loongarch, kexec: change dependency of object files
mm/damon/core: make damon_start() waits until kdamond_fn() starts
selftests/mm: cow: print ksft header before printing anything else
mm: fix VMA heap bounds checking
riscv: fix VMALLOC_START definition
kexec: drop dependency on ARCH_SUPPORTS_KEXEC from CRASH_DUMP
Pull sound fixes from Takashi Iwai:
"A collection of HD-audio quirks for TAS2781 codec and device-specific
workarounds"
* tag 'sound-6.7-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
ALSA: hda/tas2781: reset the amp before component_add
ALSA: hda/tas2781: call cleanup functions only once
ALSA: hda/tas2781: handle missing EFI calibration data
ALSA: hda/tas2781: leave hda_component in usable state
ALSA: hda/realtek: Apply mute LED quirk for HP15-db
ALSA: hda/hdmi: add force-connect quirks for ASUSTeK Z170 variants
ALSA: hda/hdmi: add force-connect quirk for NUC5CPYB
Pull drm fixes from Dave Airlie:
"More regular fixes, amdgpu, i915, mediatek and nouveau are most of
them this week. Nothing too major, then a few misc bits and pieces in
core, panel and ivpu.
drm:
- fix uninit problems in crtc
- fix fd ownership check
- edid: add modes in fallback paths
panel:
- move LG panel into DSI yaml
- ltk050h3146w: set burst mode
mediatek:
- mtk_disp_gamma: Fix breakage due to merge issue
- fix kernel oops if no crtc is found
- Add spinlock for setting vblank event in atomic_begin
- Fix access violation in mtk_drm_crtc_dma_dev_get
i915:
- Fix selftest engine reset count storage for multi-tile
- Fix out-of-bounds reads for engine reset counts
- Fix ADL+ remapped stride with CCS
- Fix intel_atomic_setup_scalers() plane_state handling
- Fix ADL+ tiled plane stride when the POT stride is smaller than the original
- Fix eDP 1.4 rate select method link configuration
amdgpu:
- Fix suspend fix that got accidently mangled last week
- Fix OD regression
- PSR fixes
- OLED Backlight regression fix
- JPEG 4.0.5 fix
- Misc display fixes
- SDMA 5.2 fix
- SDMA 2.4 regression fix
- GPUVM race fix
nouveau:
- fix gk20a instobj hierarchy
- fix headless iors inheritance regression
ivpu:
- fix WA initialisation"
* tag 'drm-fixes-2023-12-15' of git://anongit.freedesktop.org/drm/drm: (31 commits)
drm/nouveau/kms/nv50-: Don't allow inheritance of headless iors
drm/nouveau: Fixup gk20a instobj hierarchy
drm/amdgpu: warn when there are still mappings when a BO is destroyed v2
drm/amdgpu: fix tear down order in amdgpu_vm_pt_free
drm/amd: Fix a probing order problem on SDMA 2.4
drm/amdgpu/sdma5.2: add begin/end_use ring callbacks
drm/panel: ltk050h3146w: Set burst mode for ltk050h3148w
dt-bindings: panel-simple-dsi: move LG 5" HD TFT LCD panel into DSI yaml
drm/amd/display: Disable PSR-SU on Parade 0803 TCON again
drm/amd/display: Populate dtbclk from bounding box
drm/amd/display: Revert "Fix conversions between bytes and KB"
drm/amdgpu/jpeg: configure doorbell for each playback
drm/amd/display: Restore guard against default backlight value < 1 nit
drm/amd/display: fix hw rotated modes when PSR-SU is enabled
drm/amd/pm: fix pp_*clk_od typo
drm/amdgpu: fix buffer funcs setting order on suspend harder
drm/mediatek: Fix access violation in mtk_drm_crtc_dma_dev_get
drm/edid: also call add modes in EDID connector update fallback
drm/i915/edp: don't write to DP_LINK_BW_SET when using rate select
drm/i915: Fix ADL+ tiled plane stride when the POT stride is smaller than the original
...
The following race can cause rb_time_read() to observe a corrupted time
stamp:
rb_time_cmpxchg()
[...]
if (!rb_time_read_cmpxchg(&t->msb, msb, msb2))
return false;
if (!rb_time_read_cmpxchg(&t->top, top, top2))
return false;
<interrupted before updating bottom>
__rb_time_read()
[...]
do {
c = local_read(&t->cnt);
top = local_read(&t->top);
bottom = local_read(&t->bottom);
msb = local_read(&t->msb);
} while (c != local_read(&t->cnt));
*cnt = rb_time_cnt(top);
/* If top and msb counts don't match, this interrupted a write */
if (*cnt != rb_time_cnt(msb))
return false;
^ this check fails to catch that "bottom" is still not updated.
So the old "bottom" value is returned, which is wrong.
Fix this by checking that all three of msb, top, and bottom 2-bit cnt
values match.
The reason to favor checking all three fields over requiring a specific
update order for both rb_time_set() and rb_time_cmpxchg() is because
checking all three fields is more robust to handle partial failures of
rb_time_cmpxchg() when interrupted by nested rb_time_set().
Link: https://lore.kernel.org/lkml/20231211201324.652870-1-mathieu.desnoyers@efficios.com/
Link: https://lore.kernel.org/linux-trace-kernel/20231212193049.680122-1-mathieu.desnoyers@efficios.com
Fixes: f458a14534 ("ring-buffer: Test last update in 32bit version of __rb_time_read()")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
