The printk code is already hard enough to understand. Remove an
unnecessary indirection by renaming vprintk_func to vprintk (adding
the asmlinkage annotation), and removing the vprintk definition from
printk.c. That way, printk is implemented in terms of vprintk as one
would expect, and there's no "vprintk_func, what's that? Some function
pointer that gets set where?"
The declaration of vprintk in linux/printk.h already has the
__printf(1,0) attribute, there's no point repeating that with the
definition - it's for diagnostics in callers.
linux/printk.h already contains a static inline {return 0;} definition
of vprintk when !CONFIG_PRINTK.
Since the corresponding stub definition of vprintk_func was not marked
"static inline", any translation unit including internal.h would get a
definition of vprintk_func - it just so happens that for
!CONFIG_PRINTK, there is precisely one such TU, namely printk.c. Had
there been more, it would be a link error; now it's just a silly waste
of a few bytes of .text, which one must assume are rather precious to
anyone disabling PRINTK.
$ objdump -dr kernel/printk/printk.o
00000330 <vprintk_func>:
330: 31 c0 xor %eax,%eax
332: c3 ret
333: 8d b4 26 00 00 00 00 lea 0x0(%esi,%eiz,1),%esi
33a: 8d b6 00 00 00 00 lea 0x0(%esi),%esi
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210323144201.486050-1-linux@rasmusvillemoes.dk
Rather than storing the iterator information in the registered
kmsg_dumper structure, create a separate iterator structure. The
kmsg_dump_iter structure can reside on the stack of the caller, thus
allowing lockless use of the kmsg_dump functions.
Update code that accesses the kernel logs using the kmsg_dumper
structure to use the new kmsg_dump_iter structure. For kmsg_dumpers,
this also means adding a call to kmsg_dump_rewind() to initialize
the iterator.
All this is in preparation for removal of @logbuf_lock.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org> # pstore
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210303101528.29901-13-john.ogness@linutronix.de
All 6 kmsg_dumpers do not benefit from the @active flag:
(provide their own synchronization)
- arch/powerpc/kernel/nvram_64.c
- arch/um/kernel/kmsg_dump.c
- drivers/mtd/mtdoops.c
- fs/pstore/platform.c
(only dump on KMSG_DUMP_PANIC, which does not require
synchronization)
- arch/powerpc/platforms/powernv/opal-kmsg.c
- drivers/hv/vmbus_drv.c
The other 2 kmsg_dump users also do not rely on @active:
(hard-code @active to always be true)
- arch/powerpc/xmon/xmon.c
- kernel/debug/kdb/kdb_main.c
Therefore, @active can be removed.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210303101528.29901-12-john.ogness@linutronix.de
The global variables @syslog_seq, @syslog_partial, @syslog_time
and write access to @clear_seq are protected by @logbuf_lock.
Once @logbuf_lock is removed, these variables will need their
own synchronization method. Introduce @syslog_lock for this
purpose.
@syslog_lock is a raw_spin_lock for now. This simplifies the
transition to removing @logbuf_lock. Once @logbuf_lock and the
safe buffers are removed, @syslog_lock can change to spin_lock.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210303101528.29901-11-john.ogness@linutronix.de
kmsg_dump_get_buffer() requires nearly the same logic as
syslog_print_all(), but uses different variable names and
does not make use of the ringbuffer loop macros. Modify
kmsg_dump_get_buffer() so that the implementation is as similar
to syslog_print_all() as possible.
A follow-up commit will move this common logic into a
separate helper function.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210303101528.29901-6-john.ogness@linutronix.de
The second loop of syslog_print_all() subtracts lengths that were
added in the first loop. With commit b031a684bf ("printk: remove
logbuf_lock writer-protection of ringbuffer") it is possible that
records are (over)written during syslog_print_all(). This allows the
possibility of the second loop subtracting lengths that were never
added in the first loop.
This situation can result in syslog_print_all() filling the buffer
starting from a later record, even though there may have been room
to fit the earlier record(s) as well.
Fixes: b031a684bf ("printk: remove logbuf_lock writer-protection of ringbuffer")
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210303101528.29901-4-john.ogness@linutronix.de
The kmsg_dumper can be called from any context and CPU, possibly
from multiple CPUs simultaneously. Since the writing of the buffer
can occur from a later scheduled work queue, the oops buffer must
be protected against simultaneous dumping.
Use an atomic bit to mark when the buffer is protected. Release the
protection in between setting the buffer and the actual writing in
order for a possible panic (immediate write) to be written during
the scheduling of a previous oops (delayed write).
An atomic bit (rather than a spinlock) was chosen so that no
scheduling or preemption side-effects would be introduced. The MTD
kmsg_dumper may dump directly or it may be delayed (via scheduled
work). Depending on the context, different MTD callbacks are used.
For example, mtd_write() expects to be called in a non-atomic
context and may take a mutex.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210303101528.29901-3-john.ogness@linutronix.de
Pull printk updates from Petr Mladek:
- New "no_hash_pointers" kernel parameter causes that %p shows raw
pointer values instead of hashed ones. It is intended only for
debugging purposes. Misuse is prevented by a fat warning message that
is inspired by trace_printk().
- Prevent a possible deadlock when flushing printk_safe buffers during
panic().
- Fix performance regression caused by the lockless printk ringbuffer.
It was visible with huge log buffer and long messages.
- Documentation fix-up.
* tag 'printk-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
lib/vsprintf: no_hash_pointers prints all addresses as unhashed
kselftest: add support for skipped tests
lib: use KSTM_MODULE_GLOBALS macro in kselftest drivers
printk: avoid prb_first_valid_seq() where possible
printk: fix deadlock when kernel panic
printk: rectify kernel-doc for prb_rec_init_wr()
Pull KUnit updates from Shuah Khan
- support for filtering test suites using glob from Daniel Latypov.
"kunit_filter.glob" command line option is passed to the UML
kernel, which currently only supports filtering by suite name.
This support allows running different subsets of tests, e.g.
$ ./tools/testing/kunit/kunit.py build
$ ./tools/testing/kunit/kunit.py exec 'list*'
$ ./tools/testing/kunit/kunit.py exec 'kunit*'
- several fixes and cleanups also from Daniel Latypov.
* tag 'linux-kselftest-kunit-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
kunit: tool: fix unintentional statefulness in run_kernel()
kunit: tool: add support for filtering suites by glob
kunit: add kunit.filter_glob cmdline option to filter suites
kunit: don't show `1 == 1` in failed assertion messages
kunit: make kunit_tool accept optional path to .kunitconfig fragment
Documentation: kunit: add tips.rst for small examples
KUnit: Docs: make start.rst example Kconfig follow style.rst
kunit: tool: simplify kconfig is_subset_of() logic
minor: kunit: tool: fix unit test so it can run from non-root dir
kunit: tool: use `with open()` in unit test
kunit: tool: stop using bare asserts in unit test
kunit: tool: fix unit test cleanup handling
Pull Kselftest updates from Shuah Khan:
- dmabuf-heaps test fixes and cleanups from John Stultz
- seccomp test fix to accept any valid fd in user_notification_addfd
- Minor fixes to breakpoints and vDSO tests
- Minor code cleanups to ipc and x86 tests
* tag 'linux-kselftest-next-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
selftests/seccomp: Accept any valid fd in user_notification_addfd
selftests/timens: add futex binary to .gitignore
selftests: breakpoints: Use correct error messages in breakpoint_test_arm64.c
selftests/vDSO: fix ABI selftest on riscv
selftests/x86/ldt_gdt: remove unneeded semicolon
selftests/ipc: remove unneeded semicolon
kselftests: dmabuf-heaps: Add extra checking that allocated buffers are zeroed
kselftests: dmabuf-heaps: Cleanup test output
kselftests: dmabuf-heaps: Softly fail if don't find a vgem device
kselftests: dmabuf-heaps: Add clearer checks on DMABUF_BEGIN/END_SYNC
kselftests: dmabuf-heaps: Fix Makefile's inclusion of the kernel's usr/include dir
Pull documentation updates from Jonathan Corbet:
"It has been a relatively quiet cycle in docsland.
- As promised, the minimum Sphinx version to build the docs is now
1.7, and we have dropped support for Python 2 entirely. That
allowed the removal of a bunch of compatibility code.
- A set of treewide warning fixups from Mauro that I applied after it
became clear nobody else was going to deal with them.
- The automarkup mechanism can now create cross-references from
relative paths to RST files.
- More translations, typo fixes, and warning fixes"
* tag 'docs-5.12' of git://git.lwn.net/linux: (75 commits)
docs: kernel-hacking: be more civil
docs: Remove the Microsoft rhetoric
Documentation/admin-guide: kernel-parameters: Update nohlt section
doc/admin-guide: fix spelling mistake: "perfomance" -> "performance"
docs: Document cross-referencing using relative path
docs: Enable usage of relative paths to docs on automarkup
docs: thermal: fix spelling mistakes
Documentation: admin-guide: Update kvm/xen config option
docs: Make syscalls' helpers naming consistent
coding-style.rst: Avoid comma statements
Documentation: /proc/loadavg: add 3 more field descriptions
Documentation/submitting-patches: Add blurb about backtraces in commit messages
Docs: drop Python 2 support
Move our minimum Sphinx version to 1.7
Documentation: input: define ABS_PRESSURE/ABS_MT_PRESSURE resolution as grams
scripts/kernel-doc: add internal hyperlink to DOC: sections
Update Documentation/admin-guide/sysctl/fs.rst
docs: Update DTB format references
docs: zh_CN: add iio index.rst translation
docs/zh_CN: add iio ep93xx_adc.rst translation
...
Pull block IPI updates from Jens Axboe:
"Avoid IRQ locking for the block IPI handling (Sebastian Andrzej
Siewior)"
* tag 'for-5.12/block-ipi-2021-02-21' of git://git.kernel.dk/linux-block:
blk-mq: Use llist_head for blk_cpu_done
blk-mq: Always complete remote completions requests in softirq
smp: Process pending softirqs in flush_smp_call_function_from_idle()
Pull iommu updates from Joerg Roedel:
- ARM SMMU and Mediatek updates from Will Deacon:
- Support for MT8192 IOMMU from Mediatek
- Arm v7s io-pgtable extensions for MT8192
- Removal of TLBI_ON_MAP quirk
- New Qualcomm compatible strings
- Allow SVA without hardware broadcast TLB maintenance on SMMUv3
- Virtualization Host Extension support for SMMUv3 (SVA)
- Allow SMMUv3 PMU perf driver to be built independently from IOMMU
- Some tidy-up in IOVA and core code
- Conversion of the AMD IOMMU code to use the generic IO-page-table
framework
- Intel VT-d updates from Lu Baolu:
- Audit capability consistency among different IOMMUs
- Add SATC reporting structure support
- Add iotlb_sync_map callback support
- SDHI support for Renesas IOMMU driver
- Misc cleanups and other small improvments
* tag 'iommu-updates-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: (94 commits)
iommu/amd: Fix performance counter initialization
MAINTAINERS: repair file pattern in MEDIATEK IOMMU DRIVER
iommu/mediatek: Fix error code in probe()
iommu/mediatek: Fix unsigned domid comparison with less than zero
iommu/vt-d: Parse SATC reporting structure
iommu/vt-d: Add new enum value and structure for SATC
iommu/vt-d: Add iotlb_sync_map callback
iommu/vt-d: Move capability check code to cap_audit files
iommu/vt-d: Audit IOMMU Capabilities and add helper functions
iommu/vt-d: Fix 'physical' typos
iommu: Properly pass gfp_t in _iommu_map() to avoid atomic sleeping
iommu/vt-d: Fix compile error [-Werror=implicit-function-declaration]
driver/perf: Remove ARM_SMMU_V3_PMU dependency on ARM_SMMU_V3
MAINTAINERS: Add entry for MediaTek IOMMU
iommu/mediatek: Add mt8192 support
iommu/mediatek: Remove unnecessary check in attach_device
iommu/mediatek: Support master use iova over 32bit
iommu/mediatek: Add iova reserved function
iommu/mediatek: Support for multi domains
iommu/mediatek: Add get_domain_id from dev->dma_range_map
...
Pull rdma updates from Jason Gunthorpe:
"This is quite a small cycle, if not for Lee's 70 patches cleaning the
kdocs it would be well below typical for patch count.
Most of the interesting work here was in the HNS and rxe drivers which
got fairly major internal changes.
Summary:
- Driver updates and bug fixes: siw, hns, bnxt_re, mlx5, efa
- Significant rework in rxe to get it ready to have XRC support added
- Several rts bug fixes
- Big series to get to 'make W=1' cleanness, primarily updating kdocs
- Support for creating a RDMA MR from a DMABUF fd to allow PCI peer
to peer transfers to GPU VRAM
- Device disassociation now works properly with umad
- Work to support more than 255 ports on a RDMA device
- Further support for the new HNS HIP09 hardware
- Coding style cleanups: comma to semicolon, unneded semicolon/blank
lines, remove 'h' printk format, don't check for NULL before kfree,
use true/false for bool"
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (205 commits)
RDMA/rtrs-srv: Do not pass a valid pointer to PTR_ERR()
RDMA/srp: Fix support for unpopulated and unbalanced NUMA nodes
RDMA/mlx5: Fail QP creation if the device can not support the CQE TS
RDMA/mlx5: Allow CQ creation without attached EQs
RDMA/rtrs-srv-sysfs: fix missing put_device
RDMA/rtrs-srv: fix memory leak by missing kobject free
RDMA/rtrs: Only allow addition of path to an already established session
RDMA/rtrs-srv: Fix stack-out-of-bounds
RDMA/rxe: Remove unused pkt->offset
RDMA/ucma: Fix use-after-free bug in ucma_create_uevent
RDMA/core: Fix kernel doc warnings for ib_port_immutable_read()
RDMA/qedr: Use true and false for bool variable
RDMA/hns: Adjust definition of FRMR fields
RDMA/hns: Refactor process of posting CMDQ
RDMA/hns: Adjust fields and variables about CMDQ tail/head
RDMA/hns: Remove redundant operations on CMDQ
RDMA/hns: Fixes missing error code of CMDQ
RDMA/hns: Remove unused member and variable of CMDQ
RDMA/ipoib: Remove racy Subnet Manager sendonly join checks
RDMA/mlx5: Support 400Gbps IB rate in mlx5 driver
...
Pull SCSI updates from James Bottomley:
"This series consists of the usual driver updates (ufs, ibmvfc,
qla2xxx, hisi_sas, pm80xx) plus the removal of the gdth driver (which
is bound to cause conflicts with a trivial change somewhere).
The only big major rework of note is the one from Hannes trying to
clean up our result handling code in the drivers to make it
consistent"
* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (194 commits)
scsi: MAINTAINERS: Adjust to reflect gdth scsi driver removal
scsi: ufs: Give clk scaling min gear a value
scsi: lpfc: Fix 'physical' typos
scsi: megaraid_mbox: Fix spelling of 'allocated'
scsi: qla2xxx: Simplify the calculation of variables
scsi: message: fusion: Fix 'physical' typos
scsi: target: core: Change ASCQ for residual write
scsi: target: core: Signal WRITE residuals
scsi: target: core: Set residuals for 4Kn devices
scsi: hisi_sas: Add trace FIFO debugfs support
scsi: hisi_sas: Flush workqueue in hisi_sas_v3_remove()
scsi: hisi_sas: Enable debugfs support by default
scsi: hisi_sas: Don't check .nr_hw_queues in hisi_sas_task_prep()
scsi: hisi_sas: Remove deferred probe check in hisi_sas_v2_probe()
scsi: lpfc: Add auto select on IRQ_POLL
scsi: ncr53c8xx: Fix typos
scsi: lpfc: Fix ancient double free
scsi: qla2xxx: Fix some memory corruption
scsi: qla2xxx: Remove redundant NULL check
scsi: megaraid: Fix ifnullfree.cocci warnings
...
Bhaskar Chowdhury
Rasmus Villemoes
John Ogness
Linus Torvalds