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Constant pointer arithmetic on a PTR_TO_FLOW_KEYS register lands the
constant in reg->var_off (e.g. flow_keys(imm=4096)), but the
PTR_TO_FLOW_KEYS path in check_mem_access() passes only insn->off to
check_flow_keys_access() and never folds reg->var_off.value. The
verifier therefore accepts an access that, at runtime, dereferences past
struct bpf_flow_keys -- a verifier/runtime divergence that yields an
out-of-bounds read and write of kernel stack memory.
Commit 022ac0750883 ("bpf: use reg->var_off instead of reg->off for
pointers") removed the generic "off += reg->off" that check_mem_access()
applied before the per-type dispatch and replaced it with per-path
folding of reg->var_off.value (for example the ctx path now folds the
register offset via check_ctx_access()). The PTR_TO_FLOW_KEYS path was
not given the equivalent fold, so a constant offset that used to be
folded and rejected is now silently accepted:
before 022ac0750883: the offset stays in reg->off and is folded
generically, so the access is checked with off=4096 and rejected.
after 022ac0750883: the offset lands in reg->var_off, the flow_keys
path checks off=0 and accepts; at runtime the access dereferences
base + 0x1000.
For a BPF_PROG_TYPE_FLOW_DISSECTOR program the following is accepted:
r2 = *(u64 *)(r1 + 144) ; R2=flow_keys (PTR_TO_FLOW_KEYS)
r2 += 0x1000 ; R2=flow_keys(imm=4096), accepted
r0 = *(u64 *)(r2 + 0) ; accepted, var_off.value=0x1000 ignored
while the equivalent insn->off form
r0 = *(u64 *)(r2 + 0x1000)
has the same effective offset but is correctly rejected with
"invalid access to flow keys off=4096 size=8", which isolates the defect
to the missing var_off fold. Once attached as a flow dissector, the
accepted program reads kernel stack past struct bpf_flow_keys (a
kernel-stack / KASLR information leak) and can likewise write past it,
corrupting kernel memory.
Fix it by folding reg->var_off.value into the offset before the bounds
check and rejecting non-constant offsets, mirroring the other pointer
types (e.g. check_ctx_access()).
Fixes: 022ac0750883 ("bpf: use reg->var_off instead of reg->off for pointers")
Signed-off-by: Nuoqi Gui <gnq25@mails.tsinghua.edu.cn>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260606-c3-01-v3-v3-1-97c51f592f15@mails.tsinghua.edu.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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After commit 0652a3daa787 ("tracing: Fix CFI violation in probestub
being called by tprobes"), there are many build errors when building
ARCH=arm multi_v7_defconfig + CONFIG_CFI=y like:
In file included from drivers/base/devres.c:17:
In file included from drivers/base/trace.h:16:
In file included from include/linux/tracepoint.h:23:
include/linux/cfi.h:44:6: error: call to undeclared function 'get_kernel_nofault'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
44 | if (get_kernel_nofault(hash, func - cfi_get_offset()))
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1 error generated.
get_kernel_nofault() is called in the generic version of
cfi_get_func_hash() but nothing ensures uaccess.h is always included for
a proper expansion and prototype. Include uaccess.h in cfi.h to clear
up the errors.
Cc: stable@vger.kernel.org
Fixes: 0652a3daa787 ("tracing: Fix CFI violation in probestub being called by tprobes")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Rework the driver to use modern style:
- Remove global state by introducing a per-device structure
- Use devm for resource management (input device allocation)
- Use dev_err_probe() for error reporting in the probe path
- Clean up unused definitions and headers.
Assisted-by: Gemini:gemini-3.1-pro
Link: https://patch.msgid.link/ahp6qt_viW3l-NlX@google.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
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Simplify resource mapping by using devm_platform_ioremap_resource()
instead of the longer devm_platform_get_and_ioremap_resource() helper
as the last argument is NULL.
Additionally, use platform_get_irq() to retrieve the interrupt
instead of irq_of_parse_and_map() and propagate its error code on
failure. irq_of_parse_and_map() requires irq_dispose_mapping, which is
missing.
Assisted-by: Antigravity:Gemini-3.5-Flash
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Link: https://patch.msgid.link/20260603192415.6679-1-rosenp@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
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Remove the Xilinx XPS PS/2 controller driver. This driver supports an
old Xilinx EDK IP core that is no longer in active use. The hardware
is not available on modern platforms, and the driver has no users here.
Assisted-by: opencode:big-pickle
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Acked-by: Michal Simek <michal.simek@amd.com>
Link: https://patch.msgid.link/20260603054217.442016-1-rosenp@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
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After commit 9cf6e24c9fbf17e52de9fff07f12be7565ea6d61 ("Input: atkbd -
do not skip atkbd_deactivate() when skipping ATKBD_CMD_GETID"), HONOR
BCC-N, aka HONOR MagicBook 14 2026's internal keyboard stops
working. Adding the atkbd_deactivate_fixup quirk fixes it.
DMI: HONOR BCC-N/BCC-N-PCB, BIOS 1.04 04/07/2026
Fixes: 9cf6e24c9fbf17e52de9fff07f12be7565ea6d61 ("Input: atkbd - do not skip atkbd_deactivate() when skipping ATKBD_CMD_GETID")
Reported-by: Hongfei Ren <lcrhf@outlook.com>
Link: https://github.com/colorcube/Linux-on-Honor-Magicbook-14-Pro/issues/1#issuecomment-4562679891
Tested-by: Hongfei Ren <lcrhf@outlook.com>
Cc: stable@kernel.org
Signed-off-by: Cryolitia PukNgae <cryolitia.pukngae@linux.dev>
Link: https://patch.msgid.link/20260605-honor-v1-1-78e05e491193@linux.dev
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
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struct perf_cpu.cpu is int16_t, limiting perf to 32767 CPUs. This is
part of the libperf ABI (returned by value from perf_cpu_map__cpu() and
friends), so widening it requires an ABI bump.
Add a comment on the struct definition noting this, and create a TODO
file to collect future ABI changes so they can be batched into a single
version bump.
Cc: Ian Rogers <irogers@google.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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free_idle_threads() relies on the thread priv destructor (free()) to
clean up idle_thread_runtime structs. But free() doesn't walk the
callchain_cursor linked list or the callchain_root tree allocated
by callchain_cursor__copy() and callchain_append() during --idle-hist
processing. Every idle thread with callchain data leaks these nodes.
Introduce callchain_cursor_cleanup() to free the cursor's linked list
of callchain_cursor_node entries, and call it together with
free_callchain() in free_idle_threads() before thread__put().
Fixes: 225b24f569980ac9 ("perf sched timehist: Save callchain when entering idle")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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set_max_cpu_num() assigns the sysfs "possible" CPU count to
max_cpu_num.cpu which is int16_t (struct perf_cpu). On systems
with >32767 possible CPUs the value silently truncates, potentially
wrapping negative. This causes cpunode_map to be underallocated
and subsequent cpu__get_node() calls to read out of bounds.
The matching check for max_present_cpu_num was added by commit
c760174401f6 ("perf cpumap: Reduce cpu size from int to int16_t")
but max_cpu_num was missed. Add the same INT16_MAX guard.
Fixes: c760174401f605cf ("perf cpumap: Reduce cpu size from int to int16_t")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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cpu2y() indexes topology_map[cpu] without bounds checking. The array
is allocated with nr_cpus entries (from env->nr_cpus_online), but
callers pass sample CPU values from perf.data which can exceed that
size with cross-machine recordings.
Track the topology_map allocation size and bounds-check the CPU
argument in cpu2y() before indexing. Out-of-bounds CPUs fall back
to the identity mapping (cpu2slot(cpu)), which is the same behavior
as when no topology is available.
Fixes: c507999790438cde ("perf timechart: Add support for topology")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Stanislav Fomichev <stfomichev@yandex-team.ru>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
Pull sound fixes from Takashi Iwai:
"It's getting calmer, but we still came up with a handful of small
fixes, including two core fixes. All look sane and safe.
Core:
- Fix wait queue list corruption in snd_pcm_drain() on linked streams
- Fix UMP event stack overread in seq dummy driver
USB-audio:
- Add quirk for AB13X USB Audio
- Fix the regression with sticky mixer volumes in 7.1-rc
ASoC:
- Fix 32-slot TDM breakage on Freescale SAI
- Varioud DMI quirks for AMD ACP"
* tag 'sound-7.1-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
ALSA: seq: dummy: fix UMP event stack overread
ALSA: usb-audio: Add iface reset and delay quirk for AB13X USB Audio
ALSA: PCM: Fix wait queue list corruption in snd_pcm_drain() on linked streams
ASoC: amd: acp70: add standalone RT721 SoundWire machine
ASoC: amd: yc: Add MSI Raider A18 HX A9WJG to quirk table
ASoC: fsl_sai: Fix 32 slots TDM broken by integer shift UB in xMR write
ASoC: amd: yc: Enable internal mic on MSI Bravo 17 C7VF
ASoC: amd: acp: Add DMI quirk for Lenovo Yoga Pro 7 15ASH11
ALSA: usb-audio: Set the value of potential sticky mixers to maximum
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he__get_c2c_hists() assigns c2c_he->hists before calling
c2c_hists__init(). If init fails, the error path calls free(hists)
but leaves c2c_he->hists pointing to freed memory. On teardown,
c2c_he_free() finds the non-NULL pointer and calls
hists__delete_entries() on it, causing a use-after-free.
Set c2c_he->hists to NULL before freeing so teardown skips the
already-freed allocation.
Fixes: b2252ae67b687d2b ("perf c2c report: Decode c2c_stats for hist entries")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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process_cpu_topology() in header.c frees env->cpu on old-format
perf.data files that predate topology information, but leaves
nr_cpus_avail set. The six perf_env__get_*_aggr_by_cpu() functions
in builtin-stat.c pass the bounds check but dereference a NULL
env->cpu pointer, crashing on old recordings.
Introduce perf_env__get_cpu_topology() as a safe accessor that
validates env->cpu, cpu.cpu >= 0, and cpu.cpu < nr_cpus_avail in
one place, returning a struct cpu_topology_map pointer or NULL.
Convert all six topology aggregation callbacks to use it.
Fixes: 88031a0de7d68d13 ("perf stat: Switch to cpu version of cpu_map__get()")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux
Pull Rust fixes from Miguel Ojeda:
"Toolchain and infrastructure:
- Fix 'rustc-option' (the Makefile one) when cross-compiling that
leads to build or boot failures in certain configs
- Work around a Rust compiler bug (already fixed for Rust 1.98.0)
thats lead to boot failures in certain configs due to missing
'uwtable' LLVM module flags
- Support a Rust compiler change (starting with Rust 1.98.0) in the
unstable target specification JSON files
- Forbid Rust + arm + KASAN configs, which do not build
'kernel' crate:
- Fix NOMMU build by adding a missing helper"
* tag 'rust-fixes-7.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux:
rust: x86: support Rust >= 1.98.0 target spec
rust: arm64: set uwtable llvm module flag for CONFIG_UNWIND_TABLES
rust: helpers: add is_vmalloc_addr wrapper for NOMMU builds
rust: kasan/kbuild: fix rustc-option when cross-compiling
ARM: Do not select HAVE_RUST when KASAN is enabled
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The recent runtime state locking cleanup converted several PCM ioctl state
checks to snd_pcm_get_state(), including snd_pcm_pre_prepare(),
snd_pcm_drain() and snd_pcm_kernel_ioctl(). The native and compat xfer
ioctl paths still sample runtime->state directly before dispatching to the
PCM transfer helpers, and snd_pcm_common_ioctl() still samples the
DISCONNECTED state directly in its common precheck.
Use snd_pcm_get_state() for those ioctl-side prechecks as well. This keeps
the externally visible ioctl entry checks consistent with the stream-locked
state access used by the recent PCM state-read cleanup.
Fixes: 032322b44c02 ("ALSA: pcm: oss: use proper stream lock for runtime->state access")
Signed-off-by: Cássio Gabriel <cassiogabrielcontato@gmail.com>
Link: https://patch.msgid.link/20260605-alsa-pcm-xfer-state-helper-v1-1-eba97cecf820@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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snd_seq_expand_var_event_at() clamps the number of bytes to copy to the
remaining variable-event length, but passes the original buffer size to
expand_var_event().
For SNDRV_SEQ_EXT_USRPTR events, expand_var_event() copies exactly the
size argument from userspace. On the final chunk, when the remaining
event data is shorter than the caller's buffer, this can read past the
declared event data and can spuriously fail with -EFAULT if the extra
bytes cross an unmapped page.
Pass the clamped length instead. The chained and kernel-backed paths
already reclamp in dump_var_event(), but the user-pointer path handles
the size directly.
Fixes: ea46f79709b6 ("ALSA: seq: Add snd_seq_expand_var_event_at() helper")
Signed-off-by: HyeongJun An <sammiee5311@gmail.com>
Link: https://patch.msgid.link/20260606040913.230213-1-sammiee5311@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Use a flexible array member to combine allocations. No need to have them
separate as they are always together.
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Link: https://patch.msgid.link/20260521232020.261405-1-rosenp@gmail.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>
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The old platform data code that used this is gone and this serves no
purpose.
The modern way to disable bands is ieee80211-freq-limit, which is
already implemented.
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Link: https://patch.msgid.link/20260521231806.261220-1-rosenp@gmail.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>
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This array is fully initialized in the loop itself. No need to zero
initialize and then overwrite.
Remove static from the array. This was a holdover from when the array
was a static global variable. It no longer confers any benefit.
Also add a min() call to avoid the manual if/ternary operation.
Assisted-by: Codex:GPT-5.5
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Link: https://patch.msgid.link/20260517222136.1660347-1-rosenp@gmail.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>
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Clear ath9k DMA descriptors with explicit status word stores instead of
memset(). The descriptor rings are coherent DMA memory, which may be
mapped uncached on 32-bit powerpc. The optimized memset() path can use
dcbz there and trigger an alignment warning.
Use WRITE_ONCE() for the descriptor status words so the compiler keeps
the clears as ordinary stores instead of folding them back into bulk
memset(). This covers AR9003 TX status descriptors as well as the RX
status area cleared when setting up RX descriptors.
Assisted-by: Codex:GPT-5.5
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Link: https://patch.msgid.link/20260517042716.2218386-1-rosenp@gmail.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>
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This follows the pattern with other USB Wifi drivers. There is nothing
special being done in the _init and _exit functions here. Simplifies and
saves some lines of code.
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Link: https://patch.msgid.link/20260506234848.189840-1-rosenp@gmail.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>
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Avoid allocating separately with a flexible array member. Simplifies
allocation slightly.
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Reviewed-by: Loic Poulain <loic.poulain@oss.qualcomm.com>
Link: https://patch.msgid.link/20260519020317.635011-1-rosenp@gmail.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>
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Fix three spelling mistakes in the DMA Transfer Engine (DXE)
description comment at the top of dxe.c.
No functional change.
Signed-off-by: Stepan Ionichev <sozdayvek@gmail.com>
Link: https://patch.msgid.link/20260503165832.1675-1-sozdayvek@gmail.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>
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The firmware response length is only checked against sizeof(*rsp) (20
bytes), but when candidate_cnt >= 1, a 22-byte candidate struct is read
at buf + 20 without verifying the response contains it. This causes an
out-of-bounds read of stale heap data, corrupting the BA session state.
Add validation that the response includes the candidate data.
Fixes: 16be1ac55944 ("wcn36xx: Parse trigger_ba response properly")
Signed-off-by: Tristan Madani <tristan@talencesecurity.com>
Reviewed-by: Loic Poulain <loic.poulain@oss.qualcomm.com>
Link: https://patch.msgid.link/20260421135018.352774-4-tristmd@gmail.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>
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The firmware-controlled rsp->count field is used as the loop bound for
indexing into the flexible rsp->regs[] array without validation against
the message length. A count exceeding the actual data causes out-of-
bounds reads from the heap-allocated message buffer.
Add a check that count fits within the received message.
Fixes: 43efa3c0f241 ("wcn36xx: Implement print_reg indication")
Signed-off-by: Tristan Madani <tristan@talencesecurity.com>
Reviewed-by: Loic Poulain <loic.poulain@oss.qualcomm.com>
Link: https://patch.msgid.link/20260421135018.352774-3-tristmd@gmail.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>
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The firmware response dispatcher copies all synchronous HAL responses
into the 4096-byte hal_buf without validating the response length. A
response exceeding WCN36XX_HAL_BUF_SIZE causes a heap buffer overflow
with firmware-controlled content.
Add a bounds check on the response length.
Fixes: 8e84c2582169 ("wcn36xx: mac80211 driver for Qualcomm WCN3660/WCN3680 hardware")
Signed-off-by: Tristan Madani <tristan@talencesecurity.com>
Reviewed-by: Loic Poulain <loic.poulain@oss.qualcomm.com>
Link: https://patch.msgid.link/20260421135018.352774-2-tristmd@gmail.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs fixes from Christian Brauner:
- Fix error handling in ovl_cache_get()
- Tighten access checks for exited tasks in pidfd_getfd()
- Fix selftests leak in __wait_for_test()
- Limit FUSE_NOTIFY_RETRIEVE to uptodate folios
- Reject fuse_notify() pagecache ops on directories
- Clear JOBCTL_PENDING_MASK for caller in zap_other_threads()
- Fix failure to unlock in nfsd4_create_file()
- Fix pointer arithmetic in qnx6 directory iteration
- Fix UAF due to unlocked ->mnt_ns read in may_decode_fh()
- Avoid potential null folio->mapping deref during iomap error
reporting
* tag 'vfs-7.1-rc7.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
iomap: avoid potential null folio->mapping deref during error reporting
fhandle: fix UAF due to unlocked ->mnt_ns read in may_decode_fh()
fs/qnx6: fix pointer arithmetic in directory iteration
VFS: fix possible failure to unlock in nfsd4_create_file()
signal: clear JOBCTL_PENDING_MASK for caller in zap_other_threads()
fuse: reject fuse_notify() pagecache ops on directories
fuse: limit FUSE_NOTIFY_RETRIEVE to uptodate folios
selftests: harness: fix pidfd leak in __wait_for_test
pidfd: refuse access to tasks that have started exiting harder
ovl: keep err zero after successful ovl_cache_get()
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When `I2cAdapter::get` executes, it first calls
`bindings::i2c_get_adapter()` which increments the device and module
reference counts. It then takes a reference to the raw pointer and
converts it to an `ARef` via `.into()`.
The implementation of `From<&T> for ARef<T>` where `T: AlwaysRefCounted`
unconditionally calls `T::inc_ref()`. This leads to a second increment
to the reference counts.
Since the returned `ARef` will only release a single reference when
dropped via `dec_ref()`, this leaks one device and module reference count
on every call.
This fix was suggested by sashiko.dev.
Link: https://sashiko.dev/#/patchset/20260521190937.248904-1-nico.antinori.7@gmail.com
Signed-off-by: Nicolás Antinori <nico.antinori.7@gmail.com>
Reviewed-by: Igor Korotin <igor.korotin@linux.dev>
Signed-off-by: Igor Korotin <igor.korotin@linux.dev>
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perf_mmap__aio_mmap() sets map->aio.nr_cblocks before allocating the
data array. If calloc() for aiocb or cblocks fails before the data
array is allocated, the return -1 path leads to perf_mmap__aio_munmap()
which loops nr_cblocks times calling perf_mmap__aio_free(). Both
versions of perf_mmap__aio_free() (NUMA and non-NUMA) dereference
map->aio.data[idx] without checking if data is NULL, causing a NULL
pointer dereference.
Add NULL checks for map->aio.data at the top of both
perf_mmap__aio_free() variants so the cleanup path is safe when
allocation fails partway through perf_mmap__aio_mmap().
Fixes: d3d1af6f011a553a ("perf record: Enable asynchronous trace writing")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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A recent build failure[1] exposed the diffculty of working with the
current octal and hex definitions of O_ flags when trying to find a gap
for a new flag. This difficulty is compounded by the fact that O_ flags
may have architectural specific values.
Replace the hex/octal #defines, which are hard to parse when looking for
free bits, with explicit bit shifts like (1 << 11). Also, add comments
that identify which architectures redefine some of the seemingly free
("cursed") bits in uapi/asm-generic/fcntl.h. These should not be used to
define new O_ flags (for now, at least).
The translastion was done with Claude Opus 4.8, and verified with a
(non-AI) gawk script. The accounting of which architectures claim
which bit-gaps in uapi/asm-generic/fcntl.h is also done by hand.
[1]: https://lore.kernel.org/all/agruPPybCx8q2XcJ@sirena.org.uk/
Assisted-by: Claude:Opus 4.8
Signed-off-by: Jori Koolstra <jkoolstra@xs4all.nl>
Link: https://patch.msgid.link/20260604222405.5382-1-jkoolstra@xs4all.nl
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
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Add a sleepable BPF kfunc that resolves the real inode backing a dentry
via d_real_inode(). On overlay/union filesystems the inode attached to
the dentry is the overlay inode which does not carry the underlying
device information. d_real_inode() resolves through the overlay and
returns the inode from the lower, real filesystem.
This is used in the RestrictFilesytemAccess bpf program that has been
merged into systemd a little while ago.
Link: https://github.com/systemd/systemd/pull/41340 [1]
Link: https://patch.msgid.link/20260526-work-bpf-verity-v2-1-cd0b1850d31b@kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
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Add support for extended attributes on bpffs inodes so that user space
and BPF LSM programs can attach metadata, for example, a content hash
or a security label - to a pinned object or directory. BPF LSM or user
space tooling can then uniformly look at this (e.g. security.bpf.*) in
similar way to other fs'es. The store is in-memory and non-persistent:
it lives only for the lifetime of the mount, like everything else in
bpffs. The modelling is similar to tmpfs.
bpffs serves the trusted.* and security.* namespaces; user.* is left
unsupported. As bpffs is FS_USERNS_MOUNT, security.* is reachable by
the unprivileged mounter in a user namespace, and thus we are using
the simple_xattr_set_limited infra there (trusted.* needs global
CAP_SYS_ADMIN).
bpf_fill_super() is open-coded instead of using simple_fill_super(),
because the root inode must now be allocated through bpf_fs_alloc_inode()
i.e. carry the bpf_fs_inode wrapper and come from the right cache -
which requires s_op (and s_xattr) to be installed before the first
inode is created. While at it, also harden s_iflags with SB_I_NOEXEC
and SB_I_NODEV.
bpf_fs_listxattr() is only reachable through the filesystem via
i_op->listxattr, so the BPF token inode is left untouched. Name-based
fsetxattr()/fgetxattr() on a token fd still work since the get/set
handlers are installed at the superblock.
For security.* namespace, we use simple_xattr_set_limited() but
there was no simple_xattr_add_limited() API yet which was needed
in bpf_fs_initxattrs() to avoid underflows in the accounting. The
symlink target is freed in bpf_free_inode() rather than in
bpf_destroy_inode() so that it is released only after an RCU grace
period, as an RCU path walk following the symlink may still
dereference inode->i_link in security_inode_follow_link(). Lastly,
the bpf_symlink() allocated the symlink target is switched to
GFP_KERNEL_ACCOUNT, so the string is charged to the caller's memcg.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://patch.msgid.link/20260602074012.416289-1-daniel@iogearbox.net
Cc: Christian Brauner <brauner@kernel.org>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
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After commit 12e9e3cd03b5 ("simpe_xattr: use per-sb cache"),
kernfs_xattr_set() and kernfs_xattr_get() compute the cache via
kernfs_root(kn) before any other check. kernfs_root(kn) walks
kn->__parent first and falls back to kn->dir.root, both of which are
NULL on a freshly kmem_cache_zalloc()'d kn. kn->__parent was being set
in kernfs_new_node() after __kernfs_new_node() returned, and kn->dir.root
is set even later by kernfs_create_dir_ns() / kernfs_create_empty_dir().
The LSM kernfs_init_security hook is invoked from inside
__kernfs_new_node(), before either field has been initialized.
selinux_kernfs_init_security() ends with kernfs_xattr_set(kn,
XATTR_NAME_SELINUX, ...). kernfs_root(kn) then returns NULL, and
&((struct kernfs_root *)NULL)->xa_cache evaluates to
offsetof(struct kernfs_root, xa_cache) which faults:
BUG: kernel NULL pointer dereference, address: 00000000000000e0
RIP: 0010:simple_xattr_set+0x27/0x8b0
Call Trace:
kernfs_xattr_set+0x63/0xb0
selinux_kernfs_init_security+0x13b/0x270
security_kernfs_init_security+0x36/0xc0
__kernfs_new_node+0x182/0x290
kernfs_new_node+0x80/0xc0
kernfs_create_dir_ns+0x2b/0xa0
cgroup_create+0x116/0x380
cgroup_mkdir+0x7c/0x1a0
Reproduces deterministically at PID 1 (systemd) on an SELinux-enabled
distro. The first cgroup mkdir under /sys/fs/cgroup with a labelled
parent panics the kernel.
The LSM hook's contract is that the kn_dir argument is the parent of
the new kn, so kn->__parent should already point at kn_dir when the
hook runs. Move kernfs_get(parent) and rcu_assign_pointer of
kn->__parent from kernfs_new_node() into __kernfs_new_node() right
before the security hook, and unwind the parent reference on the
err_out4 path. kernfs_root(kn) then takes its parent branch during
the hook and returns parent->dir.root, which is the correct root.
This also closes the same-shape latent bug in kernfs_xattr_get() (which
today is hidden only by kernfs_iattrs_noalloc() returning NULL on a
fresh kn).
Fixes: 12e9e3cd03b5 ("simpe_xattr: use per-sb cache")
Reported-by: Calum Mackay <calum.mackay@oracle.com>
Closes: https://lore.kernel.org/all/5386153f-9112-4971-98fc-de90d7aae2c6@oracle.com/
Link: https://patch.msgid.link/20260526-ablief-demut-wehen-aef8446ef5c9@brauner
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
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Christian Brauner (Amutable) <brauner@kernel.org> says:
Rework the simple xattrs api to make it more efficient and easier to
use for all consumers.
* patches from https://patch.msgid.link/20260605135322.2632068-1-mszeredi@redhat.com:
simpe_xattr: use per-sb cache
simple_xattr: change interface to pass struct simple_xattrs **
tmpfs: simplify constructing "security.foo" xattr names
kernfs: fix xattr race condition with multiple superblocks
Link: https://patch.msgid.link/20260605135322.2632068-1-mszeredi@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Move the hash table to the super block to remove excessive overhead in case
of small number of xattrs per inode.
Add linked list to the inode, used for listxattr and eviction. Listxattr
uses rcu protection to iterate the list of xattrs.
Before being made per-sb, lazy allocation was protected by inode lock. Now
inode lock no longer provides sufficient exclusion, so use cmpxchg() to
ensure atomicity.
Though I haven't found a description of this pattern, after some research
it seems that cmpxchg_release() and READ_ONCE() should provide the
necessary memory barriers.
Use simple_xattr_free_rcu() in simple_xattrs_free(). This is needed because
the hash table is now shared between inodes and lookup on a different inode
might be running the compare function on the just freed element within the
RCU grace period.
Following stats are based on slabinfo diff, after creating 100k empty
files, then adding a "user.test=foo" xattr to each:
v7.0 (no rhashtable):
File creation: 993.40 bytes/file
Xattr addition: 79.99 bytes/file
v7.1-rc2 (per-inode rhashtable):
File creation: 939.73 bytes/file
Xattr addition: 1296.08 bytes/file
v7.1-rc2 + this patch (per-sb rhashtable)
File creation: 946.84 bytes/file
Xattr addition: 111.86 bytes/file
The overhead of a single xattr is reduced to nearly v7.0 levels. The per
xattr overhead is slightly larger due to the addition of three pointers to
struct simple_xattr.
Fixes: b32c4a213698 ("xattr: add rhashtable-based simple_xattr infrastructure")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Link: https://patch.msgid.link/20260605135322.2632068-5-mszeredi@redhat.com
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
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Change the simple_xattr API to accept pointer-to-pointer (struct
simple_xattrs **) instead of pointer. This allows the functions to handle
lazy allocation internally without requiring callers to use
simple_xattrs_lazy_alloc().
The simple_xattr_set(), simple_xattr_set_limited() and simple_xattr_add()
functions now handle allocation when xattrs is NULL. simple_xattrs_free()
now also frees the xattrs structure itself and sets the pointer to NULL.
This simplifies callers and removes the need for most callers to explicitly
manage xattrs allocation and lifetime.
In shmem_initxattrs(), the total required space for all initial xattrs
(ispace) is pre-calculated and deducted from sbinfo->free_ispace.
Since this patch modifies the function to add new xattrs directly to the
inode's &info->xattrs list rather than using a local temporary variable, a
failure means that the partially populated info->xattrs list remains
attached to the inode.
When the VFS caller handles the -ENOMEM error, it drops the newly created
inode via iput(), shmem_free_inode() adds freed to sbinfo->free_ispace a
second time, permanently inflating the tmpfs free space quota.
Fix by substracting already added xattrs from ispace.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Link: https://patch.msgid.link/20260605135322.2632068-4-mszeredi@redhat.com
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
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Use kasprintf() instead of doing it with kmalloc() + 2 x memcpy().
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Link: https://patch.msgid.link/20260605135322.2632068-3-mszeredi@redhat.com
Tested-by: Calum Mackay <calum.mackay@oracle.com>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
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Multiple superblocks with different namespaces can share the same
kernfs_node when kernfs_test_super() finds a matching root but
different namespace. This means multiple inodes from different
superblocks can reference the same kernfs_node->iattr->xattrs
structure.
The VFS layer only holds per-inode locks during xattr operations,
which is insufficient to serialize concurrent xattr modifications on
the shared kernfs_node. This can lead to race conditions in
simple_xattr_set() where the lookup->replace/remove sequence is not
atomic with respect to operations from other superblocks.
Fix this by protecting xattr operations with the existing hashed
kernfs_locks->open_file_mutex[] array, which is already used to
protect per-node open file data. The hashed mutex array provides
scalable per-node serialization (scaled by CPU count, up to 1024 locks
on 32+ CPU systems) with zero memory overhead.
Changes:
- Rename open_file_mutex[] to node_mutex[] to reflect dual purpose
- Add kernfs_node_lock_ptr() and kernfs_node_lock() helpers
- Protect simple_xattr_set() calls in kernfs_xattr_set() and
kernfs_vfs_user_xattr_set() with the hashed mutex
- Update file.c to use new helpers via compatibility wrappers
- Update documentation to explain the extended lock usage
Fixes: b32c4a213698 ("xattr: add rhashtable-based simple_xattr infrastructure")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260601162454.2116375-1-mszeredi%40redhat.com
Assisted-by: Claude:claude-sonnet-4-5
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Link: https://patch.msgid.link/20260605135322.2632068-2-mszeredi@redhat.com
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
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When booting a debug PREEMPT_RT kernel on an ARM64 system, a "inconsistent
{HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage" lockdep warning message was
reported to the console.
During early boot, interrupts are enabled before the scheduler is
enabled. In this window (before SYSTEM_SCHEDULING is set) interrupts can
fire and in the hard interrupt context handler attempt to fill the pool
This can lead to a deadlock when the interrupt occurred when the interrupt
hits a region which holds a lock that is required to be taken in the
allocation path.
Add a new can_fill_pool() helper and reorder the exception rule and forbid
this scenario by excluding allocations from hard interrupt context.
Fixes: 06e0ae988f6e ("debugobjects: Allow to refill the pool before SYSTEM_SCHEDULING")
Suggested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260605173038.495075-1-longman@redhat.com
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rust-next
Pull pin-init updates from Gary Guo:
"User visible changes:
- Do not generate 'non_snake_case' warnings for identifiers that are
syntactically just users of a field name. This would allow all
'#[allow(non_snake_case)]' in nova-core to be removed, which I will
send to the nova tree next cycle.
- Filter non-cfg attributes out properly in derived structs. This
improves pin-init compatibility with other derive macros.
- Insert projection types' where clause properly.
Other changes:
- Bump MSRV to 1.82, plus associated cleanups.
- Overhaul how init slots are projected. The new approach is easier
to justify with safety comments.
- Mark more functions as inline, which should help mitigate the
super-long symbol name issue due to lack of inlining.
- Various small code quality cleanups."
* tag 'pin-init-v7.2' of https://github.com/Rust-for-Linux/linux: (27 commits)
rust: pin_init: internal: use `loop {}` to produce never value
rust: pin-init: remove `E` from `InitClosure`
rust: pin-init: move `InitClosure` out from `__internal`
rust: pin-init: docs: fix typos in MaybeZeroable documentation
rust: pin-init: internal: suppress `non_snake_case` lint in `[pin_]init!`
rust: pin-init: internal: suppress `non_snake_case` lint in `#[pin_data]`
rust: pin-init: internal: pin_data: filter non-`#[cfg]` attr in generated code
rust: pin-init: internal: project using full slot
rust: pin-init: internal: project slots instead of references
rust: pin-init: internal: make `make_closure` inherent methods
rust: pin-init: internal: use marker on drop guard type for pinned fields
rust: pin-init: internal: init: handle code blocks early
rust: pin-init: internal: add `PhantomInvariant` and `PhantomInvariantLifetime`
rust: pin-init: internal: pin_data: add struct to record field info
rust: pin-init: internal: pin_data: use closure for `handle_field`
rust: pin-init: examples: fix `useless_borrows_in_formatting` clippy warning
rust: pin-init: internal: remove `collect_tuple` polyfill after MSRV bump
rust: pin-init: internal: turn `PhantomPinned` error into warnings
rust: pin-init: cleanup workaround for old Rust compiler
rust: pin-init: fix badge URL in README
...
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The CONFIG_PROPELLER_CLANG option currently depends on
ARCH_SUPPORTS_PROPELLER_CLANG, but this dependency seems unnecessary.
Remove ARCH_SUPPORTS_PROPELLER_CLANG and allow users to control
Propeller builds solely through CONFIG_PROPELLER_CLANG. This simplifies
the kconfig and avoids potential confusion.
Move the .llvm_bb_addr_map sections grouping to
include/asm-generic/vmlinux.lds.h.
The Propeller documentation has been updated to reflect the most
recent tool location and now includes instructions for arm64.
Contributor Acknowledgments:
* SPE instructions: Daniel Hoekwater <hoekwater@google.com>
Signed-off-by: Rong Xu <xur@google.com>
Suggested-by: Will Deacon <will@kernel.org>
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Yabin Cui <yabinc@google.com>
Reviewed-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20260604195612.3757860-3-xur@google.com
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
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The CONFIG_AUTOFDO_CLANG option currently depends on
ARCH_SUPPORTS_AUTOFDO_CLANG, but this dependency seems unnecessary.
Remove ARCH_SUPPORTS_AUTOFDO_CLANG and allow users to control AutoFDO
builds solely through CONFIG_AUTOFDO_CLANG. This simplifies the kconfig
and avoids potential confusion.
Expand the AutoFDO documentation to include instructions for arm64.
Contributor acknowledgments:
* SPE instructions: Daniel Hoekwater <hoekwater@google.com>
* ETM instructions: Yabin Cui <yabinc@google.com>
Signed-off-by: Rong Xu <xur@google.com>
Suggested-by: Will Deacon <will@kernel.org>
Tested-by: Yabin Cui <yabinc@google.com>
Reviewed-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20260604195612.3757860-2-xur@google.com
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
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Modpost emits hundreds of warnings when using Clang to build for ARCH=um
and CONFIG_GCOV=y. e.g.:
vmlinux (__llvm_covfun): unexpected non-allocatable section.
Did you forget to use "ax"/"aw" in a .S file?
Note that for example <linux/init.h> contains
section definitions for use in .S files.
For example, when we use LLVM for a kunit user mode build with coverage:
python3 tools/testing/kunit/kunit.py build --make_options LLVM=1 \
--kunitconfig=tools/testing/kunit/configs/default.config \
--kunitconfig=tools/testing/kunit/configs/coverage_uml.config
The behaviour occurs when building the kernel for ARCH=um with code
coverage enabled. The warnings come from modpost's check_sec_ref
function, which ensures no sections reference others that will be
discarded. covfun and covmap sections must reference __init and __exit
sections to collect coverage data, triggering the modpost warning.
To suppress these warnings, these section names have been added to
modpost's whitelist. This is unlikely to suppress legitimate warnings as
Clang will only insert these sections when building with coverage, and
can be assumed to manage these references safely.
Signed-off-by: James Lee <james@codeconstruct.com.au>
Link: https://patch.msgid.link/20260604-dev-coverage-patch-v1-1-9f9368253cb4@codeconstruct.com.au
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
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Add a minimal BPF LSM program on lsm/bpf_prog_load that, for loads on
the monitored thread, reads back prog->aux->sig.{verdict,keyring_type,
keyring_serial}, and a signed_loader subtest that drives the same
gen_loader loader through the hook twice: i) /unsigned/ where the LSM
must observe UNSIGNED, no keyring and serial 0; ii) /signed/ where the
very same insns signed against the session keyring must be observed as
VERIFIED with a user keyring, and the recorded keyring_serial must be
equal to the resolved session keyring serial. Loading (not running) the
loader is sufficient since the verdict is attached at load time.
# LDLIBS=-static PKG_CONFIG='pkg-config --static' ./vmtest.sh -- ./test_progs -t signed_loader
[ 1.970530] clocksource: Switched to clocksource tsc
#405/1 signed_loader/metadata_check_shape:OK
#405/2 signed_loader/metadata_match:OK
#405/3 signed_loader/metadata_sha_mismatch:OK
#405/4 signed_loader/metadata_not_exclusive:OK
#405/5 signed_loader/metadata_hash_not_computed:OK
#405/6 signed_loader/signature_enforced:OK
#405/7 signed_loader/signature_too_large:OK
#405/8 signed_loader/signature_bad_keyring:OK
#405/9 signed_loader/metadata_ctx_max_entries_ignored:OK
#405/10 signed_loader/metadata_ctx_initial_value_ignored:OK
#405/11 signed_loader/signature_authenticates_insns:OK
#405/12 signed_loader/hash_requires_frozen:OK
#405/13 signed_loader/no_update_after_freeze:OK
#405/14 signed_loader/freeze_writable_mmap:OK
#405/15 signed_loader/no_writable_mmap_frozen:OK
#405/16 signed_loader/map_hash_matches_libbpf:OK
#405/17 signed_loader/map_hash_multi_element:OK
#405/18 signed_loader/map_hash_bad_size:OK
#405/19 signed_loader/map_hash_unsupported_type:OK
#405/20 signed_loader/lsm_signature_verdict:OK
#405 signed_loader:OK
Summary: 1/20 PASSED, 0 SKIPPED, 0 FAILED
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20260605213518.544262-2-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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BPF_PROG_LOAD verifies the loader signature but does not record the
outcome on the BPF program. [BPF] LSMs and audit can read attr->signature
and attr->keyring_id to infer "was this signed, and if so, against which
keyring".
Add prog->aux->sig (verdict + keyring_{type,serial}), populated by
bpf_prog_load before the LSM hook. keyring_type classifies the keyring
the load referenced (builtin, secondary, platform or user), while
keyring_serial records the serial of the keyring the signature was
actually validated against. System keyrings carry a pseudo key pointer
with no user-visible serial and are reported as 0, as are unsigned loads.
Failed verifications reject the load before the hook runs, so it observes
only either UNSIGNED or VERIFIED.
Signed-off-by: KP Singh <kpsingh@kernel.org>
Co-developed-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20260605213518.544262-1-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Emil Tsalapatis says:
====================
selftests/bpf: libarena: Add initial data structures
Add two new data structures to libarena. These data structures initially
resided in the sched-ext repo (https://github.com/sched-ext/scx) and
have been adapted to the internal libarena build system. The data
structures are:
- Red black tree: Fundamental tree data structure that can also serve
as a base for more domain-specific data structures.
- Lev-Chase deque: Queue data structure that allows efficient work
stealing, useful in scheduling scenarios.
The data structures are accompanied by selftests that are automatically
discovered by the existing libarena test_progs selftest and incorporated
in the CI.
CHANGELOG
=========
v3 -> v4 (https://lore.kernel.org/bpf/20260604235016.20856-1-emil@etsalapatis.com/)
- Turn off load_acquire/store_relesase - dependent selftests for s390 (CI)
- Various style/non-functional nits (AI)
v2 -> v3 (https://lore.kernel.org/bpf/20260603182727.3922-1-emil@etsalapatis.com/)
- Add workaround to handle LLVM 21 and GCC 15 assignment-to-memset promotions
that are causing verification failures for arena programs (CI)
- Incorporate Sashiko feedback for cleanup edge cases (Sashiko)
- Simplify some of the ordering semantics in spmc
v1 -> v2 (https://lore.kernel.org/bpf/20260511214100.9487-1-emil@etsalapatis.com/):
- Rename tests from st_ to test_ (Alexei)
- Removed the freelist caches from the rbtrees, previously used to defer freeing (Alexei)
- Moved the type and function definitions to use the __arena identifier
- Removed the typecasts during function return and directly return __arena
pointers (Alexei)
- Renamed queues to spmc queues to abstract away the algorithm (Alexei)
- Adjusted the memory barriers in the spmc queue
- Added multithreaded testing harness for libarena programs (Alexei)
- Added parallel selftest for queues (Alexei)
- Split least upper bound and exact find operations back into separate
functions to prevent RB_DUPLICATE-related bug (AI)
====================
Link: https://patch.msgid.link/20260605222020.5231-1-emil@etsalapatis.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Add a parallel test for the SPMC Lev-Chase workstealing queue. The queue
is built to be wait-free even when there are multiple consumers, and
the parallel selftest provides a signal on whether the queue behaves
correctly when stress tested.
To support the test, this patch includes a test harness for parallel
selftests. The spmc selftest acts as an example of the naming and other
conventions expected by the harness.
Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/r/20260605222020.5231-4-emil@etsalapatis.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Expand libarena with a single producer multiple consumer deque data
structure. This is a single producer, multiple consumer lockless structure
that permits efficient work stealing. The structure is a Lev-Chase queue,
so it is lock-free and wait-free.
The data structure exposes three main calls. two of them are available to
the thread owning the queue and one available to all threads in the program:
spmc_owner_push(): Push an item to the top of the queue.
spmc_owner_pop(): Pop an item from the top of the queue.
spmc_steal(): Steal a thread from the bottom of the queue from
any thread.
Note that the queue is not really FIFO for all consumers, since
non-owners of the queue can only work steal from the bottom.
Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/r/20260605222020.5231-3-emil@etsalapatis.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
