tjh.dev/kernel at v5.14-rc4

Currently --dump-raw-trace skips queueing and splitting buffers because
of an early exit condition in cs_etm__process_auxtrace_info(). Once
that is removed we can print the split data by using the queues
and searching for split buffers with the same reference as the
one that is currently being processed.

This keeps the same behaviour of dumping in file order when an AUXTRACE
event appears, rather than moving trace dump to where AUX records are in
the file.

There will be a newline and size printout for each fragment. For example
this buffer is comprised of two AUX records, but was printed as one:

0 0 0x8098 [0x30]: PERF_RECORD_AUXTRACE size: 0xa0 offset: 0 ref: 0x491a4dfc52fc0e6e idx: 0 t

. ... CoreSight ETM Trace data: size 160 bytes
Idx:0; ID:10; I_ASYNC : Alignment Synchronisation.
Idx:12; ID:10; I_TRACE_INFO : Trace Info.; INFO=0x0 { CC.0 }
Idx:17; ID:10; I_ADDR_L_64IS0 : Address, Long, 64 bit, IS0.; Addr=0x0000000000000000;
Idx:80; ID:10; I_ASYNC : Alignment Synchronisation.
Idx:92; ID:10; I_TRACE_INFO : Trace Info.; INFO=0x0 { CC.0 }
Idx:97; ID:10; I_ADDR_L_64IS0 : Address, Long, 64 bit, IS0.; Addr=0xFFFFDE2AD3FD76D4;

But is now printed as two fragments:

0 0 0x8098 [0x30]: PERF_RECORD_AUXTRACE size: 0xa0 offset: 0 ref: 0x491a4dfc52fc0e6e idx: 0 t

. ... CoreSight ETM Trace data: size 80 bytes
Idx:0; ID:10; I_ASYNC : Alignment Synchronisation.
Idx:12; ID:10; I_TRACE_INFO : Trace Info.; INFO=0x0 { CC.0 }
Idx:17; ID:10; I_ADDR_L_64IS0 : Address, Long, 64 bit, IS0.; Addr=0x0000000000000000;

. ... CoreSight ETM Trace data: size 80 bytes
Idx:80; ID:10; I_ASYNC : Alignment Synchronisation.
Idx:92; ID:10; I_TRACE_INFO : Trace Info.; INFO=0x0 { CC.0 }
Idx:97; ID:10; I_ADDR_L_64IS0 : Address, Long, 64 bit, IS0.; Addr=0xFFFFDE2AD3FD76D4;

Decoding errors that appeared in problematic files are now not present,
for example:

Idx:808; ID:1c; I_BAD_SEQUENCE : Invalid Sequence in packet.[I_ASYNC]
...
PKTP_ETMV4I_0016 : 0x0014 (OCSD_ERR_INVALID_PCKT_HDR) [Invalid packet header]; TrcIdx=822

Signed-off-by: James Clark <james.clark@arm.com>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Tested-by: Leo Yan <leo.yan@linaro.org>
Cc: Al Grant <al.grant@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Branislav Rankov <branislav.rankov@arm.com>
Cc: Denis Nikitin <denik@chromium.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lore.kernel.org/lkml/20210624164303.28632-3-james.clark@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

48e8a7b5

James Clark

4 years ago

Merge tag 'net-5.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Pull networking fixes from Jakub Kicinski:
"Networking fixes for 5.14-rc4, including fixes from bpf, can, WiFi
(mac80211) and netfilter trees.

Current release - regressions:

- mac80211: fix starting aggregation sessions on mesh interfaces

Current release - new code bugs:

- sctp: send pmtu probe only if packet loss in Search Complete state

- bnxt_en: add missing periodic PHC overflow check

- devlink: fix phys_port_name of virtual port and merge error

- hns3: change the method of obtaining default ptp cycle

- can: mcba_usb_start(): add missing urb->transfer_dma initialization

Previous releases - regressions:

- set true network header for ECN decapsulation

- mlx5e: RX, avoid possible data corruption w/ relaxed ordering and
LRO

- phy: re-add check for PHY_BRCM_DIS_TXCRXC_NOENRGY on the BCM54811
PHY

- sctp: fix return value check in __sctp_rcv_asconf_lookup

Previous releases - always broken:

- bpf:
- more spectre corner case fixes, introduce a BPF nospec
instruction for mitigating Spectre v4
- fix OOB read when printing XDP link fdinfo
- sockmap: fix cleanup related races

- mac80211: fix enabling 4-address mode on a sta vif after assoc

- can:
- raw: raw_setsockopt(): fix raw_rcv panic for sock UAF
- j1939: j1939_session_deactivate(): clarify lifetime of session
object, avoid UAF
- fix number of identical memory leaks in USB drivers

- tipc:
- do not blindly write skb_shinfo frags when doing decryption
- fix sleeping in tipc accept routine"

* tag 'net-5.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (91 commits)
gve: Update MAINTAINERS list
can: esd_usb2: fix memory leak
can: ems_usb: fix memory leak
can: usb_8dev: fix memory leak
can: mcba_usb_start(): add missing urb->transfer_dma initialization
can: hi311x: fix a signedness bug in hi3110_cmd()
MAINTAINERS: add Yasushi SHOJI as reviewer for the Microchip CAN BUS Analyzer Tool driver
bpf: Fix leakage due to insufficient speculative store bypass mitigation
bpf: Introduce BPF nospec instruction for mitigating Spectre v4
sis900: Fix missing pci_disable_device() in probe and remove
net: let flow have same hash in two directions
nfc: nfcsim: fix use after free during module unload
tulip: windbond-840: Fix missing pci_disable_device() in probe and remove
sctp: fix return value check in __sctp_rcv_asconf_lookup
nfc: s3fwrn5: fix undefined parameter values in dev_err()
net/mlx5: Fix mlx5_vport_tbl_attr chain from u16 to u32
net/mlx5e: Fix nullptr in mlx5e_hairpin_get_mdev()
net/mlx5: Unload device upon firmware fatal error
net/mlx5e: Fix page allocation failure for ptp-RQ over SF
net/mlx5e: Fix page allocation failure for trap-RQ over SF
...

c7d10223

Linus Torvalds

4 years ago

cifs: add missing parsing of backupuid

b946dbcf

Ronnie Sahlberg

4 years ago

xfs: limit iclog tail updates

From the department of "generic/482 keeps on giving", we bring you
another tail update race condition:

iclog:
S1 C1
+-----------------------+-----------------------+
S2 EOIC

Two checkpoints in a single iclog. One is complete, the other just
contains the start record and overruns into a new iclog.

Timeline:

Before S1: Cache flush, log tail = X
At S1: Metadata stable, write start record and checkpoint
At C1: Write commit record, set NEED_FUA
Single iclog checkpoint, so no need for NEED_FLUSH
Log tail still = X, so no need for NEED_FLUSH

After C1,
Before S2: Cache flush, log tail = X
At S2: Metadata stable, write start record and checkpoint
After S2: Log tail moves to X+1
At EOIC: End of iclog, more journal data to write
Releases iclog
Not a commit iclog, so no need for NEED_FLUSH
Writes log tail X+1 into iclog.

At this point, the iclog has tail X+1 and NEED_FUA set. There has
been no cache flush for the metadata between X and X+1, and the
iclog writes the new tail permanently to the log. THis is sufficient
to violate on disk metadata/journal ordering.

We have two options here. The first is to detect this case in some
manner and ensure that the partial checkpoint write sets NEED_FLUSH
when the iclog is already marked NEED_FUA and the log tail changes.
This seems somewhat fragile and quite complex to get right, and it
doesn't actually make it obvious what underlying problem it is
actually addressing from reading the code.

The second option seems much cleaner to me, because it is derived
directly from the requirements of the C1 commit record in the iclog.
That is, when we write this commit record to the iclog, we've
guaranteed that the metadata/data ordering is correct for tail
update purposes. Hence if we only write the log tail into the iclog
for the *first* commit record rather than the log tail at the last
release, we guarantee that the log tail does not move past where the
the first commit record in the log expects it to be.

IOWs, taking the first option means that replay of C1 becomes
dependent on future operations doing the right thing, not just the
C1 checkpoint itself doing the right thing. This makes log recovery
almost impossible to reason about because now we have to take into
account what might or might not have happened in the future when
looking at checkpoints in the log rather than just having to
reconstruct the past...

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

9d110014

Dave Chinner

4 years ago

branches 2

master 14 hours ago default

compare

for-next 11 months ago

compare

tags 914

v6.19-rc4

6 days ago latest

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.

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