tjh.dev
Linux kernel
============
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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.
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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When searching for config options, use the KCONFIG_CONFIG shell variable
so that builds using non-standard config locations work.
Fixes: 26deb04342e3 ("powerpc: prepare string/mem functions for KASAN")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220624011745.4060795-1-Liam.Howlett@oracle.com
Commit 2fb4706057bc ("powerpc: add support for folded p4d page tables")
erroneously changed PUD setup to a mix of PMD and PUD. Fix it.
While at it, use PTE_TABLE_SIZE instead of PAGE_SIZE for PTE tables
in order to avoid any confusion.
Fixes: 2fb4706057bc ("powerpc: add support for folded p4d page tables")
Cc: stable@vger.kernel.org # v5.8+
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/95ddfd6176d53e6c85e13bd1c358359daa56775f.1655974558.git.christophe.leroy@csgroup.eu
kasan detects access beyond the end of the xibm->bitmap allocation:
BUG: KASAN: slab-out-of-bounds in _find_first_zero_bit+0x40/0x140
Read of size 8 at addr c00000001d1d0118 by task swapper/0/1
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.19.0-rc2-00001-g90df023b36dd #28
Call Trace:
[c00000001d98f770] [c0000000012baab8] dump_stack_lvl+0xac/0x108 (unreliable)
[c00000001d98f7b0] [c00000000068faac] print_report+0x37c/0x710
[c00000001d98f880] [c0000000006902c0] kasan_report+0x110/0x354
[c00000001d98f950] [c000000000692324] __asan_load8+0xa4/0xe0
[c00000001d98f970] [c0000000011c6ed0] _find_first_zero_bit+0x40/0x140
[c00000001d98f9b0] [c0000000000dbfbc] xive_spapr_get_ipi+0xcc/0x260
[c00000001d98fa70] [c0000000000d6d28] xive_setup_cpu_ipi+0x1e8/0x450
[c00000001d98fb30] [c000000004032a20] pSeries_smp_probe+0x5c/0x118
[c00000001d98fb60] [c000000004018b44] smp_prepare_cpus+0x944/0x9ac
[c00000001d98fc90] [c000000004009f9c] kernel_init_freeable+0x2d4/0x640
[c00000001d98fd90] [c0000000000131e8] kernel_init+0x28/0x1d0
[c00000001d98fe10] [c00000000000cd54] ret_from_kernel_thread+0x5c/0x64
Allocated by task 0:
kasan_save_stack+0x34/0x70
__kasan_kmalloc+0xb4/0xf0
__kmalloc+0x268/0x540
xive_spapr_init+0x4d0/0x77c
pseries_init_irq+0x40/0x27c
init_IRQ+0x44/0x84
start_kernel+0x2a4/0x538
start_here_common+0x1c/0x20
The buggy address belongs to the object at c00000001d1d0118
which belongs to the cache kmalloc-8 of size 8
The buggy address is located 0 bytes inside of
8-byte region [c00000001d1d0118, c00000001d1d0120)
The buggy address belongs to the physical page:
page:c00c000000074740 refcount:1 mapcount:0 mapping:0000000000000000 index:0xc00000001d1d0558 pfn:0x1d1d
flags: 0x7ffff000000200(slab|node=0|zone=0|lastcpupid=0x7ffff)
raw: 007ffff000000200 c00000001d0003c8 c00000001d0003c8 c00000001d010480
raw: c00000001d1d0558 0000000001e1000a 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
c00000001d1d0000: fc 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
c00000001d1d0080: fc fc 00 fc fc fc fc fc fc fc fc fc fc fc fc fc
>c00000001d1d0100: fc fc fc 02 fc fc fc fc fc fc fc fc fc fc fc fc
^
c00000001d1d0180: fc fc fc fc 04 fc fc fc fc fc fc fc fc fc fc fc
c00000001d1d0200: fc fc fc fc fc 04 fc fc fc fc fc fc fc fc fc fc
This happens because the allocation uses the wrong unit (bits) when it
should pass (BITS_TO_LONGS(count) * sizeof(long)) or equivalent. With small
numbers of bits, the allocated object can be smaller than sizeof(long),
which results in invalid accesses.
Use bitmap_zalloc() to allocate and initialize the irq bitmap, paired with
bitmap_free() for consistency.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220623182509.3985625-1-nathanl@linux.ibm.com
The platform's RNG must be available before random_init() in order to be
useful for initial seeding, which in turn means that it needs to be
called from setup_arch(), rather than from an init call.
Complicating things, however, is that POWER8 systems need some per-cpu
state and kmalloc, which isn't available at this stage. So we split
things up into an early phase and a later opportunistic phase. This
commit also removes some noisy log messages that don't add much.
Fixes: a4da0d50b2a0 ("powerpc: Implement arch_get_random_long/int() for powernv")
Cc: stable@vger.kernel.org # v3.13+
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[mpe: Add of_node_put(), use pnv naming, minor change log editing]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220621140849.127227-1-Jason@zx2c4.com
When CONFIG_KASAN is selected, we expect prom_init to use __memset()
because it is too early to use memset().
But with CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL, the compiler adds calls
to memset() to clear objects on stack, hence the following failure:
PROMCHK arch/powerpc/kernel/prom_init_check
Error: External symbol 'memset' referenced from prom_init.c
make[2]: *** [arch/powerpc/kernel/Makefile:204 : arch/powerpc/kernel/prom_init_check] Erreur 1
prom_find_machine_type() is called from prom_init() and is called only
once, so lets put compat[] in BSS instead of stack to avoid that.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/3802811f7cf94f730be44688539c01bba3a3b5c0.1654875808.git.christophe.leroy@csgroup.eu
Add a special case to block_rtas_call() to allow the ibm,platform-dump RTAS
call through the RTAS filter if the buffer address is 0.
According to PAPR, ibm,platform-dump is called with a null buffer address
to notify the platform firmware that processing of a particular dump is
finished.
Without this, on a pseries machine with CONFIG_PPC_RTAS_FILTER enabled, an
application such as rtas_errd that is attempting to retrieve a dump will
encounter an error at the end of the retrieval process.
Fixes: bd59380c5ba4 ("powerpc/rtas: Restrict RTAS requests from userspace")
Cc: stable@vger.kernel.org
Reported-by: Sathvika Vasireddy <sathvika@linux.ibm.com>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Reviewed-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220614134952.156010-1-ajd@linux.ibm.com
On execve[at], we are zero'ing out most of the thread register state
including gpr[0], which contains the syscall number. Due to this, we
fail to trigger the syscall exit tracepoint properly. Fix this by
retaining gpr[0] in the thread register state.
Before this patch:
# tail /sys/kernel/debug/tracing/trace
cat-123 [000] ..... 61.449351: sys_execve(filename:
7fffa6b23448, argv: 7fffa6b233e0, envp: 7fffa6b233f8)
cat-124 [000] ..... 62.428481: sys_execve(filename:
7fffa6b23448, argv: 7fffa6b233e0, envp: 7fffa6b233f8)
echo-125 [000] ..... 65.813702: sys_execve(filename:
7fffa6b23378, argv: 7fffa6b233a0, envp: 7fffa6b233b0)
echo-125 [000] ..... 65.822214: sys_execveat(fd: 0,
filename: 1009ac48, argv: 7ffff65d0c98, envp: 7ffff65d0ca8, flags: 0)
After this patch:
# tail /sys/kernel/debug/tracing/trace
cat-127 [000] ..... 100.416262: sys_execve(filename:
7fffa41b3448, argv: 7fffa41b33e0, envp: 7fffa41b33f8)
cat-127 [000] ..... 100.418203: sys_execve -> 0x0
echo-128 [000] ..... 103.873968: sys_execve(filename:
7fffa41b3378, argv: 7fffa41b33a0, envp: 7fffa41b33b0)
echo-128 [000] ..... 103.875102: sys_execve -> 0x0
echo-128 [000] ..... 103.882097: sys_execveat(fd: 0,
filename: 1009ac48, argv: 7fffd10d2148, envp: 7fffd10d2158, flags: 0)
echo-128 [000] ..... 103.883225: sys_execveat -> 0x0
Cc: stable@vger.kernel.org
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Tested-by: Sumit Dubey2 <Sumit.Dubey2@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220609103328.41306-1-naveen.n.rao@linux.vnet.ibm.com
The platform's RNG must be available before random_init() in order to be
useful for initial seeding, which in turn means that it needs to be
called from setup_arch(), rather than from an init call. Fortunately,
each platform already has a setup_arch function pointer, which means
it's easy to wire this up. This commit also removes some noisy log
messages that don't add much.
Fixes: a489043f4626 ("powerpc/pseries: Implement arch_get_random_long() based on H_RANDOM")
Cc: stable@vger.kernel.org # v3.13+
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220611151015.548325-4-Jason@zx2c4.com
The platform's RNG must be available before random_init() in order to be
useful for initial seeding, which in turn means that it needs to be
called from setup_arch(), rather than from an init call. Fortunately,
each platform already has a setup_arch function pointer, which means
it's easy to wire this up. This commit also removes some noisy log
messages that don't add much.
Fixes: c25769fddaec ("powerpc/microwatt: Add support for hardware random number generator")
Cc: stable@vger.kernel.org # v5.14+
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220611151015.548325-2-Jason@zx2c4.com
After commit 11ac3e87ce09 ("mm: cma: use pageblock_order as the single
alignment") there is an error at boot about the KVM CMA reservation
failing, eg:
kvm_cma_reserve: reserving 6553 MiB for global area
cma: Failed to reserve 6553 MiB
That makes it impossible to start KVM guests using the hash MMU with
more than 2G of memory, because the VM is unable to allocate a large
enough region for the hash page table, eg:
$ qemu-system-ppc64 -enable-kvm -M pseries -m 4G ...
qemu-system-ppc64: Failed to allocate KVM HPT of order 25: Cannot allocate memory
Aneesh pointed out that this happens because when kvm_cma_reserve() is
called, pageblock_order has not been initialised yet, and is still zero,
causing the checks in cma_init_reserved_mem() against
CMA_MIN_ALIGNMENT_PAGES to fail.
Fix it by moving the call to kvm_cma_reserve() after initmem_init(). The
pageblock_order is initialised in sparse_init() which is called from
initmem_init().
Also move the hugetlb CMA reservation.
Fixes: 11ac3e87ce09 ("mm: cma: use pageblock_order as the single alignment")
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220616120033.1976732-1-mpe@ellerman.id.au
Pull x86 platform driver fixes from Hans de Goede:
"Highlights:
- Fix hp-wmi regression on HP Omen laptops introduced in 5.18
- Several hardware-id additions
- A couple of other tiny fixes"
* tag 'platform-drivers-x86-v5.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86:
platform/x86/intel: hid: Add Surface Go to VGBS allow list
platform/x86: hp-wmi: Use zero insize parameter only when supported
platform/x86: hp-wmi: Resolve WMI query failures on some devices
platform/x86: gigabyte-wmi: Add support for B450M DS3H-CF
platform/x86: gigabyte-wmi: Add Z690M AORUS ELITE AX DDR4 support
platform/x86: barco-p50-gpio: Add check for platform_driver_register
platform/x86/intel: pmc: Support Intel Raptorlake P
platform/x86/intel: Fix pmt_crashlog array reference
platform/mellanox: Add static in struct declaration.
platform/mellanox: Spelling s/platfom/platform/
Pull workqueue fixes from Tejun Heo:
"Tetsuo's patch to trigger build warnings if system-wide wq's are
flushed along with a TP type update and trivial comment update"
* tag 'wq-for-5.19-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: Switch to new kerneldoc syntax for named variable macro argument
workqueue: Fix type of cpu in trace event
workqueue: Wrap flush_workqueue() using a macro
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