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.
code
Clone this repository
https://tangled.org/tjh.dev/kernel
git@gordian.tjh.dev:tjh.dev/kernel
For self-hosted knots, clone URLs may differ based on your setup.
Pull EFI fixes from Thomas Gleixner:
"A set of EFI fixes:
- Don't return a garbage screen info when EFI framebuffer is not
available
- Make the early EFI console work properly with wider fonts instead
of drawing garbage
- Prevent a memory buffer leak in allocate_e820()
- Print the firmware error record properly so it can be decoded by
users
- Fix a symbol clash in the host tool build which only happens with
newer compilers.
- Add a missing check for the event log version of TPM which caused
boot failures on several Dell systems due to an attempt to decode
SHA-1 format with the crypto agile algorithm"
* tag 'efi-urgent-2020-05-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
tpm: check event log version before reading final events
efi: Pull up arch-specific prototype efi_systab_show_arch()
x86/boot: Mark global variables as static
efi: cper: Add support for printing Firmware Error Record Reference
efi/libstub/x86: Avoid EFI map buffer alloc in allocate_e820()
efi/earlycon: Fix early printk for wider fonts
efi/libstub: Avoid returning uninitialized data from setup_graphics()
Pull x86 fixes from Thomas Gleixner:
"Two fixes for x86:
- Unbreak stack dumps for inactive tasks by interpreting the special
first frame left by __switch_to_asm() correctly.
The recent change not to skip the first frame so ORC and frame
unwinder behave in the same way caused all entries to be
unreliable, i.e. prepended with '?'.
- Use cpumask_available() instead of an implicit NULL check of a
cpumask_var_t in mmio trace to prevent a Clang build warning"
* tag 'x86-urgent-2020-05-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/unwind/orc: Fix unwind_get_return_address_ptr() for inactive tasks
x86/mmiotrace: Use cpumask_available() for cpumask_var_t variables
Pull EFI fixes from Ard Biesheuvel:
"- fix EFI framebuffer earlycon for wide fonts
- avoid filling screen_info with garbage if the EFI framebuffer is not
available
- fix a potential host tool build error due to a symbol clash on x86
- work around a EFI firmware bug regarding the binary format of the TPM
final events table
- fix a missing memory free by reworking the E820 table sizing routine to
not do the allocation in the first place
- add CPER parsing for firmware errors"
Pull scheduler fixes from Thomas Gleixner:
"A set of fixes for the scheduler:
- Fix handling of throttled parents in enqueue_task_fair() completely.
The recent fix overlooked a corner case where the first iteration
terminates due to an entity already being on the runqueue which
makes the list management incomplete and later triggers the
assertion which checks for completeness.
- Fix a similar problem in unthrottle_cfs_rq().
- Show the correct uclamp values in procfs which prints the effective
value twice instead of requested and effective"
* tag 'sched-urgent-2020-05-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/fair: Fix unthrottle_cfs_rq() for leaf_cfs_rq list
sched/debug: Fix requested task uclamp values shown in procfs
sched/fair: Fix enqueue_task_fair() warning some more
Normally, show_trace_log_lvl() scans the stack, looking for text
addresses to print. In parallel, it unwinds the stack with
unwind_next_frame(). If the stack address matches the pointer returned
by unwind_get_return_address_ptr() for the current frame, the text
address is printed normally without a question mark. Otherwise it's
considered a breadcrumb (potentially from a previous call path) and it's
printed with a question mark to indicate that the address is unreliable
and typically can be ignored.
Since the following commit:
f1d9a2abff66 ("x86/unwind/orc: Don't skip the first frame for inactive tasks")
... for inactive tasks, show_trace_log_lvl() prints *only* unreliable
addresses (prepended with '?').
That happens because, for the first frame of an inactive task,
unwind_get_return_address_ptr() returns the wrong return address
pointer: one word *below* the task stack pointer. show_trace_log_lvl()
starts scanning at the stack pointer itself, so it never finds the first
'reliable' address, causing only guesses to being printed.
The first frame of an inactive task isn't a normal stack frame. It's
actually just an instance of 'struct inactive_task_frame' which is left
behind by __switch_to_asm(). Now that this inactive frame is actually
exposed to callers, fix unwind_get_return_address_ptr() to interpret it
properly.
Fixes: f1d9a2abff66 ("x86/unwind/orc: Don't skip the first frame for inactive tasks")
Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200522135435.vbxs7umku5pyrdbk@treble
This fixes the boot issues since 5.3 on several Dell models when the TPM
is enabled. Depending on the exact grub binary, booting the kernel would
freeze early, or just report an error parsing the final events log.
We get an event log in the SHA-1 format, which doesn't have a
tcg_efi_specid_event_head in the first event, and there is a final events
table which doesn't match the crypto agile format.
__calc_tpm2_event_size reads bad "count" and "efispecid->num_algs", and
either fails, or loops long enough for the machine to be appear frozen.
So we now only parse the final events table, which is per the spec always
supposed to be in the crypto agile format, when we got a event log in this
format.
Fixes: c46f3405692de ("tpm: Reserve the TPM final events table")
Fixes: 166a2809d65b2 ("tpm: Don't duplicate events from the final event log in the TCG2 log")
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1779611
Signed-off-by: Loïc Yhuel <loic.yhuel@gmail.com>
Link: https://lore.kernel.org/r/20200512040113.277768-1-loic.yhuel@gmail.com
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: Matthew Garrett <mjg59@google.com>
[ardb: warn when final events table is missing or in the wrong format]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Pull networking fixes from David Miller:
1) Fix RCU warnings in ipv6 multicast router code, from Madhuparna
Bhowmik.
2) Nexthop attributes aren't being checked properly because of
mis-initialized iterator, from David Ahern.
3) Revert iop_idents_reserve() change as it caused performance
regressions and was just working around what is really a UBSAN bug
in the compiler. From Yuqi Jin.
4) Read MAC address properly from ROM in bmac driver (double iteration
proceeds past end of address array), from Jeremy Kerr.
5) Add Microsoft Surface device IDs to r8152, from Marc Payne.
6) Prevent reference to freed SKB in __netif_receive_skb_core(), from
Boris Sukholitko.
7) Fix ACK discard behavior in rxrpc, from David Howells.
8) Preserve flow hash across packet scrubbing in wireguard, from Jason
A. Donenfeld.
9) Cap option length properly for SO_BINDTODEVICE in AX25, from Eric
Dumazet.
10) Fix encryption error checking in kTLS code, from Vadim Fedorenko.
11) Missing BPF prog ref release in flow dissector, from Jakub Sitnicki.
12) dst_cache must be used with BH disabled in tipc, from Eric Dumazet.
13) Fix use after free in mlxsw driver, from Jiri Pirko.
14) Order kTLS key destruction properly in mlx5 driver, from Tariq
Toukan.
15) Check devm_platform_ioremap_resource() return value properly in
several drivers, from Tiezhu Yang.
* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (71 commits)
net: smsc911x: Fix runtime PM imbalance on error
net/mlx4_core: fix a memory leak bug.
net: ethernet: ti: cpsw: fix ASSERT_RTNL() warning during suspend
net: phy: mscc: fix initialization of the MACsec protocol mode
net: stmmac: don't attach interface until resume finishes
net: Fix return value about devm_platform_ioremap_resource()
net/mlx5: Fix error flow in case of function_setup failure
net/mlx5e: CT: Correctly get flow rule
net/mlx5e: Update netdev txq on completions during closure
net/mlx5: Annotate mutex destroy for root ns
net/mlx5: Don't maintain a case of del_sw_func being null
net/mlx5: Fix cleaning unmanaged flow tables
net/mlx5: Fix memory leak in mlx5_events_init
net/mlx5e: Fix inner tirs handling
net/mlx5e: kTLS, Destroy key object after destroying the TIS
net/mlx5e: Fix allowed tc redirect merged eswitch offload cases
net/mlx5: Avoid processing commands before cmdif is ready
net/mlx5: Fix a race when moving command interface to events mode
net/mlx5: Add command entry handling completion
rxrpc: Fix a memory leak in rxkad_verify_response()
...
Although not exactly identical, unthrottle_cfs_rq() and enqueue_task_fair()
are quite close and follow the same sequence for enqueuing an entity in the
cfs hierarchy. Modify unthrottle_cfs_rq() to use the same pattern as
enqueue_task_fair(). This fixes a problem already faced with the latter and
add an optimization in the last for_each_sched_entity loop.
Fixes: fe61468b2cb (sched/fair: Fix enqueue_task_fair warning)
Reported-by Tao Zhou <zohooouoto@zoho.com.cn>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Phil Auld <pauld@redhat.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Link: https://lkml.kernel.org/r/20200513135528.4742-1-vincent.guittot@linaro.org
When building with Clang + -Wtautological-compare and
CONFIG_CPUMASK_OFFSTACK unset:
arch/x86/mm/mmio-mod.c:375:6: warning: comparison of array 'downed_cpus'
equal to a null pointer is always false [-Wtautological-pointer-compare]
if (downed_cpus == NULL &&
^~~~~~~~~~~ ~~~~
arch/x86/mm/mmio-mod.c:405:6: warning: comparison of array 'downed_cpus'
equal to a null pointer is always false [-Wtautological-pointer-compare]
if (downed_cpus == NULL || cpumask_weight(downed_cpus) == 0)
^~~~~~~~~~~ ~~~~
2 warnings generated.
Commit
f7e30f01a9e2 ("cpumask: Add helper cpumask_available()")
added cpumask_available() to fix warnings of this nature. Use that here
so that clang does not warn regardless of CONFIG_CPUMASK_OFFSTACK's
value.
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://github.com/ClangBuiltLinux/linux/issues/982
Link: https://lkml.kernel.org/r/20200408205323.44490-1-natechancellor@gmail.com
Pull IPMI update from Corey Minyard:
"Convert i2c_new_device() to i2c_new_client_device()
Wolfram Sang has asked to have this included in 5.7 so the deprecated
API can be removed next release. There should be no functional
difference.
I think that entire this section of code can be removed; it is
leftover from other things that have since changed, but this is the
safer thing to do for now. The full removal can happen next release"
* tag 'for-linus-5.7-2' of git://github.com/cminyard/linux-ipmi:
char: ipmi: convert to use i2c_new_client_device()
Pull up arch-specific prototype efi_systab_show_arch() in order to
fix a -Wmissing-prototypes warning:
arch/x86/platform/efi/efi.c:957:7: warning: no previous prototype for
‘efi_systab_show_arch’ [-Wmissing-prototypes]
char *efi_systab_show_arch(char *str)
Signed-off-by: Benjamin Thiel <b.thiel@posteo.de>
Link: https://lore.kernel.org/r/20200516132647.14568-1-b.thiel@posteo.de
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The srmmu_nocache_init() uses __nocache_fix() macro to add an offset to
page table entry to access srmmu_nocache_pool.
But since sparc32 has only three actual page table levels, pgd, p4d and
pud are essentially the same thing and pgd_offset() and p4d_offset() are
no-ops, the __nocache_fix() should be done only at PUD level.
Remove __nocache_fix() for p4d_offset() and pud_offset() and keep it
only for PUD and lower levels.
Fixes: c2bc26f7ca1f ("sparc32: use PUD rather than PGD to get PMD in srmmu_nocache_init()")
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Anatoly Pugachev <matorola@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>