Kumar Kartikeya Dwivedi says:
====================
BPF Standard Streams
This set introduces a standard output interface with two streams, namely
stdout and stderr, for BPF programs. The idea is that these streams will
be written to by BPF programs and the kernel, and serve as standard
interfaces for informing user space of any BPF runtime violations. Users
can also utilize them for printing normal messages for debugging usage,
as is the case with bpf_printk() and trace pipe interface.
BPF programs and the kernel can use these streams to output messages.
User space can dump these messages using bpftool.
The stream interface itself is implemented using a lockless list, so
that we can queue messages from any context. Every printk statement into
the stream leads to memory allocation. Allocation itself relies on
try_alloc_pages() to construct a bespoke bump allocator to carve out
elements. If this fails, we finally give up and drop the message.
See commit logs for more details.
Two scenarios are covered:
- Deadlocks and timeouts in rqspinlock.
- Timeouts for may_goto.
In each we provide the stack trace and source information for the
offending BPF programs. Both the C source line and the file and line
numbers are printed. The output format is as follows:
ERROR: AA or ABBA deadlock detected for bpf_res_spin_lock
Attempted lock = 0xff11000108f3a5e0
Total held locks = 1
Held lock[ 0] = 0xff11000108f3a5e0
CPU: 48 UID: 0 PID: 786 Comm: test_progs
Call trace:
bpf_stream_stage_dump_stack+0xb0/0xd0
bpf_prog_report_rqspinlock_violation+0x10b/0x130
bpf_res_spin_lock+0x8c/0xa0
bpf_prog_3699ea119d1f6ed8_foo+0xe5/0x140
if (!bpf_res_spin_lock(&v2->lock)) @ stream_bpftool.c:62
bpf_prog_9b324ec4a1b2a5c0_stream_bpftool_dump_prog_stream+0x7e/0x2d0
foo(stream); @ stream_bpftool.c:93
bpf_prog_test_run_syscall+0x102/0x240
__sys_bpf+0xd68/0x2bf0
__x64_sys_bpf+0x1e/0x30
do_syscall_64+0x68/0x140
entry_SYSCALL_64_after_hwframe+0x76/0x7e
ERROR: Timeout detected for may_goto instruction
CPU: 48 UID: 0 PID: 786 Comm: test_progs
Call trace:
bpf_stream_stage_dump_stack+0xb0/0xd0
bpf_prog_report_may_goto_violation+0x6a/0x90
bpf_check_timed_may_goto+0x4d/0xa0
arch_bpf_timed_may_goto+0x21/0x40
bpf_prog_3699ea119d1f6ed8_foo+0x12f/0x140
while (can_loop) @ stream_bpftool.c:71
bpf_prog_9b324ec4a1b2a5c0_stream_bpftool_dump_prog_stream+0x7e/0x2d0
foo(stream); @ stream_bpftool.c:93
bpf_prog_test_run_syscall+0x102/0x240
__sys_bpf+0xd68/0x2bf0
__x64_sys_bpf+0x1e/0x30
do_syscall_64+0x68/0x140
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Changelog:
----------
v4 -> v5
v4: https://lore.kernel.org/bpf/20250702031737.407548-1-memxor@gmail.com
* Add acks from Emil.
* Address various nits.
* Add extra failure tests.
* Make deadlock test a little more robust to catch problems.
v3 -> v4
v3: https://lore.kernel.org/bpf/20250624031252.2966759-1-memxor@gmail.com
* Switch to alloc_pages_nolock(), avoid incorrect memcg accounting. (Alexei)
* We will figure out proper accounting later.
* Drop error limit logic, restrict stream capacity to 100,000 bytes. (Alexei)
* Remove extra invocation of is_bpf_text_address(). (Jiri)
* Avoid emitting NULL byte into the stream text, adjust regex in selftests. (Alexei)
* Add comment around rcu_read_lock() for bpf_prog_ksym_find. (Alexei)
* Tighten stream capacity check selftest.
* Add acks from Andrii.
v2 -> v3
v2: https://lore.kernel.org/bpf/20250524011849.681425-1-memxor@gmail.com
* Fix bug when handling single element stream stage. (Eduard)
* Move to mutex for protection of stream read and copy_to_user(). (Alexei)
* Split bprintf refactor into its own patch. (Alexei)
* Move kfunc definition to common_btf_ids to avoid initcall proliferation. (Alexei)
* Return line number by reference in bpf_prog_get_file_line. (Alexei)
* Remove NULL checks for BTF name pointer. (Alexei)
* Add WARN_ON_ONCE(!rcu_read_lock_held()) in bpf_prog_ksym_find. (Eduard)
* Remove hardcoded stream stage from macros. (Alexei, Eduard)
* Move refactoring hunks to their own patch. (Alexei)
* Add empty opts parameter for future extensibility to libbpf API. (Andrii, Eduard)
* Add BPF_STREAM_{STDOUT,STDERR} to UAPI. (Andrii)
* Add code to match on backtrace output. (Eduard)
* Fix misc nits.
* Add acks.
v1 -> v2
v1: https://lore.kernel.org/bpf/20250507171720.1958296-1-memxor@gmail.com
* Drop arena page fault prints, will be done as follow up. (Alexei)
* Defer Andrii's request to reuse code and Alan's suggestion of error
counts to follow up.
* Drop bpf_dynptr_from_mem_slice patch.
* Drop some acks due to heavy reworking.
* Fix KASAN splat in bpf_prog_get_file_line. (Eduard)
* Collapse bpf_prog_ksym_find and is_bpf_text_address into single
call. (Eduard)
* Add missing RCU read lock in bpf_prog_ksym_find.
* Fix incorrect error handling in dump_stack_cb.
* Simplify libbpf macro. (Eduard, Andrii)
* Introduce bpf_prog_stream_read() libbpf API. (Eduard, Alexei, Andrii)
* Drop BPF prog from the bpftool, use libbpf API.
* Rework selftests.
RFC v1 -> v1
RFC v1: https://lore.kernel.org/bpf/20250414161443.1146103-1-memxor@gmail.com
* Rebase on bpf-next/master.
* Change output in dump_stack to also print source line. (Alexei)
* Simplify API to single pop() operation. (Eduard, Alexei)
* Add kdoc for bpf_dynptr_from_mem_slice.
* Fix -EINVAL returned from prog_dump_stream. (Eduard)
* Split dump_stack() patch into multiple commits.
* Add macro wrapping stream staging API.
* Change bpftool command from dump to tracelog. (Quentin)
* Add bpftool documentation and bash completion. (Quentin)
* Change license of bpftool to Dual BSD/GPL.
* Simplify memory allocator. (Alexei)
* No overflow into second page.
* Remove bpf_mem_alloc() fallback.
* Symlink bpftool BPF program and exercise as selftest. (Eduard)
* Verify output after dumping from ringbuf. (Eduard)
* More failure cases to check API invariants.
* Remove patches for dynptr lifetime fixes (split into separate set).
* Limit maximum error messages, and add stream capacity. (Eduard)
====================
Link: https://patch.msgid.link/20250703204818.925464-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add selftests to stress test the various facets of the stream API,
memory allocation pattern, and ensuring dumping support is tested and
functional.
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250703204818.925464-13-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add support for printing the BPF stream contents of a program in
bpftool. The new bpftool prog tracelog command is extended to take
stdout and stderr arguments, and then the prog specification.
The bpf_prog_stream_read() API added in previous patch is simply reused
to grab data and then it is dumped to the respective file. The stdout
data is sent to stdout, and stderr is printed to stderr.
Cc: Quentin Monnet <qmo@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250703204818.925464-12-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce a libbpf API so that users can read data from a given BPF
stream for a BPF prog fd. For now, only the low-level syscall wrapper
is provided, we can add a bpf_program__* accessor as a follow up if
needed.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250703204818.925464-11-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add a convenience macro to print data to the BPF streams. BPF_STDOUT and
BPF_STDERR stream IDs in the vmlinux.h can be passed to the macro to
print to the respective streams.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250703204818.925464-10-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce a kernel function which is the analogue of dump_stack()
printing some useful information and the stack trace. This is not
exposed to BPF programs yet, but can be made available in the future.
When we have a program counter for a BPF program in the stack trace,
also additionally output the filename and line number to make the trace
helpful. The rest of the trace can be passed into ./decode_stacktrace.sh
to obtain the line numbers for kernel symbols.
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250703204818.925464-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In preparation of figuring out the closest program that led to the
current point in the kernel, implement a function that scans through the
stack trace and finds out the closest BPF program when walking down the
stack trace.
Special care needs to be taken to skip over kernel and BPF subprog
frames. We basically scan until we find a BPF main prog frame. The
assumption is that if a program calls into us transitively, we'll
hit it along the way. If not, we end up returning NULL.
Contextually the function will be used in places where we know the
program may have called into us.
Due to reliance on arch_bpf_stack_walk(), this function only works on
x86 with CONFIG_UNWINDER_ORC, arm64, and s390. Remove the warning from
arch_bpf_stack_walk as well since we call it outside bpf_throw()
context.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250703204818.925464-6-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add a warning to ensure RCU lock is held around tree lookup, and then
fix one of the invocations in bpf_stack_walker. The program has an
active stack frame and won't disappear. Use the opportunity to remove
unneeded invocation of is_bpf_text_address.
Fixes: f18b03faba ("bpf: Implement BPF exceptions")
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250703204818.925464-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Prepare a function for use in future patches that can extract the file
info, line info, and the source line number for a given BPF program
provided it's program counter.
Only the basename of the file path is provided, given it can be
excessively long in some cases.
This will be used in later patches to print source info to the BPF
stream.
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250703204818.925464-4-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add support for a stream API to the kernel and expose related kfuncs to
BPF programs. Two streams are exposed, BPF_STDOUT and BPF_STDERR. These
can be used for printing messages that can be consumed from user space,
thus it's similar in spirit to existing trace_pipe interface.
The kernel will use the BPF_STDERR stream to notify the program of any
errors encountered at runtime. BPF programs themselves may use both
streams for writing debug messages. BPF library-like code may use
BPF_STDERR to print warnings or errors on misuse at runtime.
The implementation of a stream is as follows. Everytime a message is
emitted from the kernel (directly, or through a BPF program), a record
is allocated by bump allocating from per-cpu region backed by a page
obtained using alloc_pages_nolock(). This ensures that we can allocate
memory from any context. The eventual plan is to discard this scheme in
favor of Alexei's kmalloc_nolock() [0].
This record is then locklessly inserted into a list (llist_add()) so
that the printing side doesn't require holding any locks, and works in
any context. Each stream has a maximum capacity of 4MB of text, and each
printed message is accounted against this limit.
Messages from a program are emitted using the bpf_stream_vprintk kfunc,
which takes a stream_id argument in addition to working otherwise
similar to bpf_trace_vprintk.
The bprintf buffer helpers are extracted out to be reused for printing
the string into them before copying it into the stream, so that we can
(with the defined max limit) format a string and know its true length
before performing allocations of the stream element.
For consuming elements from a stream, we expose a bpf(2) syscall command
named BPF_PROG_STREAM_READ_BY_FD, which allows reading data from the
stream of a given prog_fd into a user space buffer. The main logic is
implemented in bpf_stream_read(). The log messages are queued in
bpf_stream::log by the bpf_stream_vprintk kfunc, and then pulled and
ordered correctly in the stream backlog.
For this purpose, we hold a lock around bpf_stream_backlog_peek(), as
llist_del_first() (if we maintained a second lockless list for the
backlog) wouldn't be safe from multiple threads anyway. Then, if we
fail to find something in the backlog log, we splice out everything from
the lockless log, and place it in the backlog log, and then return the
head of the backlog. Once the full length of the element is consumed, we
will pop it and free it.
The lockless list bpf_stream::log is a LIFO stack. Elements obtained
using a llist_del_all() operation are in LIFO order, thus would break
the chronological ordering if printed directly. Hence, this batch of
messages is first reversed. Then, it is stashed into a separate list in
the stream, i.e. the backlog_log. The head of this list is the actual
message that should always be returned to the caller. All of this is
done in bpf_stream_backlog_fill().
From the kernel side, the writing into the stream will be a bit more
involved than the typical printk. First, the kernel typically may print
a collection of messages into the stream, and parallel writers into the
stream may suffer from interleaving of messages. To ensure each group of
messages is visible atomically, we can lift the advantage of using a
lockless list for pushing in messages.
To enable this, we add a bpf_stream_stage() macro, and require kernel
users to use bpf_stream_printk statements for the passed expression to
write into the stream. Underneath the macro, we have a message staging
API, where a bpf_stream_stage object on the stack accumulates the
messages being printed into a local llist_head, and then a commit
operation splices the whole batch into the stream's lockless log list.
This is especially pertinent for rqspinlock deadlock messages printed to
program streams. After this change, we see each deadlock invocation as a
non-interleaving contiguous message without any confusion on the
reader's part, improving their user experience in debugging the fault.
While programs cannot benefit from this staged stream writing API, they
could just as well hold an rqspinlock around their print statements to
serialize messages, hence this is kept kernel-internal for now.
Overall, this infrastructure provides NMI-safe any context printing of
messages to two dedicated streams.
Later patches will add support for printing splats in case of BPF arena
page faults, rqspinlock deadlocks, and cond_break timeouts, and
integration of this facility into bpftool for dumping messages to user
space.
[0]: https://lore.kernel.org/bpf/20250501032718.65476-1-alexei.starovoitov@gmail.com
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250703204818.925464-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Refactor code to be able to get and put bprintf buffers and use
bpf_printf_prepare independently. This will be used in the next patch to
implement BPF streams support, particularly as a staging buffer for
strings that need to be formatted and then allocated and pushed into a
stream.
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250703204818.925464-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Alexei suggested, 'link_type' can be more precise and differentiate
for human in fdinfo. In fact BPF_LINK_TYPE_KPROBE_MULTI includes
kretprobe_multi type, the same as BPF_LINK_TYPE_UPROBE_MULTI, so we
can show it more concretely.
link_type: kprobe_multi
link_id: 1
prog_tag: d2b307e915f0dd37
...
link_type: kretprobe_multi
link_id: 2
prog_tag: ab9ea0545870781d
...
link_type: uprobe_multi
link_id: 9
prog_tag: e729f789e34a8eca
...
link_type: uretprobe_multi
link_id: 10
prog_tag: 7db356c03e61a4d4
Co-developed-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Tao Chen <chen.dylane@linux.dev>
Link: https://lore.kernel.org/r/20250702153958.639852-1-chen.dylane@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
To handle hardware characteristic of ADC, calibrate the function and add
a efuse field to record result, which driver uses it to set proper value
accordingly.
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20250627035201.16416-3-pkshih@realtek.com
Originally the type of path_ok is bool to denote that DPK is ready on
certain path and can be enabled. For RTL8851B, hardware design can support
more than one calibration set, so use type u8 instead to record the
hardware set in current use.
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20250627035201.16416-2-pkshih@realtek.com
In most cases zcomp_available_show() is the only emitting
function that is called from sysfs read() handler, so it
assumes that there is a whole PAGE_SIZE buffer to work with.
There is an exception, however: recomp_algorithm_show().
In recomp_algorithm_show() we prepend the buffer with
priority number before we pass it to zcomp_available_show(),
so it cannot assume PAGE_SIZE anymore and must take
recomp_algorithm_show() modifications into consideration.
Therefore we need to pass buffer offset to zcomp_available_show().
Also convert it to use sysfs_emit_at(), to stay aligned
with the rest of zram's sysfs read() handlers.
On practice we are never even close to using the whole PAGE_SIZE
buffer, so that's not a critical bug, but still.
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Link: https://lore.kernel.org/r/20250627071840.1394242-1-senozhatsky@chromium.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Replace scnprintf() with sysfs_emit() or sysfs_emit_at() in sysfs
*_show() functions in zram_drv.c to follow the kernel's guidelines
from Documentation/filesystems/sysfs.rst.
This improves consistency, safety, and makes the code easier to
maintain and update in the future.
Signed-off-by: Rahul Kumar <rk0006818@gmail.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Link: https://lore.kernel.org/r/20250627035256.1120740-1-rk0006818@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The pll1_d8 clock is enabled by the boot loader, and is ultimately a
parent for numerous clocks, including those used by APB and AXI buses.
Guodong Xu discovered that this clock got disabled while responding to
getting -EPROBE_DEFER when requesting a reset controller.
The needed clock (CLK_DMA, along with its parents) had already been
enabled. To respond to the probe deferral return, the CLK_DMA clock
was disabled, and this led to parent clocks also reducing their enable
count. When the enable count for pll1_d8 was decremented it became 0,
which caused it to be disabled. This led to a system hang.
Marking that clock critical resolves this by preventing it from being
disabled.
Define a new macro CCU_FACTOR_GATE_DEFINE() to allow clock flags to
be supplied for a CCU_FACTOR_GATE clock.
Fixes: 1b72c59db0 ("clk: spacemit: Add clock support for SpacemiT K1 SoC")
Signed-off-by: Alex Elder <elder@riscstar.com>
Tested-by: Guodong Xu <guodong@riscstar.com>
Reviewed-by: Haylen Chu <heylenay@4d2.org>
Link: https://lore.kernel.org/r/20250612224856.1105924-1-elder@riscstar.com
Signed-off-by: Yixun Lan <dlan@gentoo.org>
There's one case where ->d_compare() can be called for an in-lookup
dentry; usually that's nothing special from ->d_compare() point of
view, but... proc_sys_compare() is weird.
The thing is, /proc/sys subdirectories can look differently for
different processes. Up to and including having the same name
resolve to different dentries - all of them hashed.
The way it's done is ->d_compare() refusing to admit a match unless
this dentry is supposed to be visible to this caller. The information
needed to discriminate between them is stored in inode; it is set
during proc_sys_lookup() and until it's done d_splice_alias() we really
can't tell who should that dentry be visible for.
Normally there's no negative dentries in /proc/sys; we can run into
a dying dentry in RCU dcache lookup, but those can be safely rejected.
However, ->d_compare() is also called for in-lookup dentries, before
they get positive - or hashed, for that matter. In case of match
we will wait until dentry leaves in-lookup state and repeat ->d_compare()
afterwards. In other words, the right behaviour is to treat the
name match as sufficient for in-lookup dentries; if dentry is not
for us, we'll see that when we recheck once proc_sys_lookup() is
done with it.
While we are at it, fix the misspelled READ_ONCE and WRITE_ONCE there.
Fixes: d9171b9345 ("parallel lookups machinery, part 4 (and last)")
Reported-by: NeilBrown <neilb@brown.name>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Define syscon nodes for the RCPU, RCPU2, and APBC2 SpacemiT CCUS, which
currently support resets but not clocks in the SpacemiT K1.
Signed-off-by: Alex Elder <elder@riscstar.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Yixun Lan <dlan@gentoo.org>
Link: https://lore.kernel.org/r/20250702113709.291748-7-elder@riscstar.com
Signed-off-by: Yixun Lan <dlan@gentoo.org>
- Fix chunking the PTE updates and overflowing the maximum number of
dwords with with MI_STORE_DATA_IMM (Jia Yao)
- Move WA BB to the LRC BO to mitigate hangs on context switch (Matthew
Brost)
- Fix frequency/flush WAs for BMG (Vinay / Lucas)
- Fix kconfig prompt title and description (Lucas)
- Do not require kunit (Harry Austen / Lucas)
- Extend 14018094691 WA to BMG (Daniele)
- Fix wedging the device on signal (Matthew Brost)
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Merge tag 'drm-xe-fixes-2025-07-03' of https://gitlab.freedesktop.org/drm/xe/kernel into drm-fixes
Driver Changes:
- Fix chunking the PTE updates and overflowing the maximum number of
dwords with with MI_STORE_DATA_IMM (Jia Yao)
- Move WA BB to the LRC BO to mitigate hangs on context switch (Matthew
Brost)
- Fix frequency/flush WAs for BMG (Vinay / Lucas)
- Fix kconfig prompt title and description (Lucas)
- Do not require kunit (Harry Austen / Lucas)
- Extend 14018094691 WA to BMG (Daniele)
- Fix wedging the device on signal (Matthew Brost)
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://lore.kernel.org/r/o5662wz6nrlf6xt5sjgxq5oe6qoujefzywuwblm3m626hreifv@foqayqydd6ig
We've seen customers having shares mounted in paths like /??/C:/ or
/??/UNC/foo.example.com/share in order to get their native SMB
symlinks successfully followed from different mounts.
After commit 12b466eb52 ("cifs: Fix creating and resolving absolute NT-style symlinks"),
the client would then convert absolute paths from "/??/C:/" to "/mnt/c/"
by default. The absolute paths would vary depending on the value of
symlinkroot= mount option.
Fix this by restoring old behavior of not trying to convert absolute
paths by default. Only do this if symlinkroot= was _explicitly_ set.
Before patch:
$ mount.cifs //w22-fs0/test2 /mnt/1 -o vers=3.1.1,username=xxx,password=yyy
$ ls -l /mnt/1/symlink2
lrwxr-xr-x 1 root root 15 Jun 20 14:22 /mnt/1/symlink2 -> /mnt/c/testfile
$ mkdir -p /??/C:; echo foo > //??/C:/testfile
$ cat /mnt/1/symlink2
cat: /mnt/1/symlink2: No such file or directory
After patch:
$ mount.cifs //w22-fs0/test2 /mnt/1 -o vers=3.1.1,username=xxx,password=yyy
$ ls -l /mnt/1/symlink2
lrwxr-xr-x 1 root root 15 Jun 20 14:22 /mnt/1/symlink2 -> '/??/C:/testfile'
$ mkdir -p /??/C:; echo foo > //??/C:/testfile
$ cat /mnt/1/symlink2
foo
Cc: linux-cifs@vger.kernel.org
Reported-by: Pierguido Lambri <plambri@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Stefan Metzmacher <metze@samba.org>
Fixes: 12b466eb52 ("cifs: Fix creating and resolving absolute NT-style symlinks")
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
When the SMB server reboots and the client immediately accesses the mount
point, a race condition can occur that causes operations to fail with
"Host is down" error.
Reproduction steps:
# Mount SMB share
mount -t cifs //192.168.245.109/TEST /mnt/ -o xxxx
ls /mnt
# Reboot server
ssh root@192.168.245.109 reboot
ssh root@192.168.245.109 /path/to/cifs_server_setup.sh
ssh root@192.168.245.109 systemctl stop firewalld
# Immediate access fails
ls /mnt
ls: cannot access '/mnt': Host is down
# But works if there is a delay
The issue is caused by a race condition between negotiate and reconnect.
The 20-second negotiate timeout mechanism can interfere with the normal
recovery process when both are triggered simultaneously.
ls cifsd
---------------------------------------------------
cifs_getattr
cifs_revalidate_dentry
cifs_get_inode_info
cifs_get_fattr
smb2_query_path_info
smb2_compound_op
SMB2_open_init
smb2_reconnect
cifs_negotiate_protocol
smb2_negotiate
cifs_send_recv
smb_send_rqst
wait_for_response
cifs_demultiplex_thread
cifs_read_from_socket
cifs_readv_from_socket
server_unresponsive
cifs_reconnect
__cifs_reconnect
cifs_abort_connection
mid->mid_state = MID_RETRY_NEEDED
cifs_wake_up_task
cifs_sync_mid_result
// case MID_RETRY_NEEDED
rc = -EAGAIN;
// In smb2_negotiate()
rc = -EHOSTDOWN;
The server_unresponsive() timeout triggers cifs_reconnect(), which aborts
ongoing mid requests and causes the ls command to receive -EAGAIN, leading
to -EHOSTDOWN.
Fix this by introducing a dedicated `neg_start` field to
precisely tracks when the negotiate process begins. The timeout check
now uses this accurate timestamp instead of `lstrp`, ensuring that:
1. Timeout is only triggered after negotiate has actually run for 20s
2. The mechanism doesn't interfere with concurrent recovery processes
3. Uninitialized timestamps (value 0) don't trigger false timeouts
Fixes: 7ccc146546 ("smb: client: fix hang in wait_for_response() for negproto")
Signed-off-by: Wang Zhaolong <wangzhaolong@huaweicloud.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
. Switch from %pK to %p for pointer formatting, as %p is now safer
and prevents issues like raw pointer leakage and acquiring sleeping
locks in atomic contexts.
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Merge tag 'samsung-dsim-fixes-for-v6.16-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/daeinki/drm-exynos into drm-fixes
- Fixed raw pointer leakage and unsafe behavior in printk()
. Switch from %pK to %p for pointer formatting, as %p is now safer
and prevents issues like raw pointer leakage and acquiring sleeping
locks in atomic contexts.
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Inki Dae <inki.dae@samsung.com>
Link: https://lore.kernel.org/r/20250629091742.29956-1-inki.dae@samsung.com
- Fixed raw pointer leakage and unsafe behavior in printk()
. Switch from %pK to %p for pointer formatting, as %p is now safer
and prevents issues like raw pointer leakage and acquiring sleeping
locks in atomic contexts.
- Fixed kernel panic during boot
. A NULL pointer dereference issue occasionally occurred
when the vblank interrupt handler was called before
the DRM driver was fully initialized during boot.
So this patch fixes the issue by adding a check in the interrupt handler
to ensure the DRM driver is properly initialized.
- Fixed a lockup issue on Samsung Peach-Pit/Pi Chromebooks
. The issue occurred after commit c9b1150a68 changed
the call order of CRTC enable/disable and bridge pre_enable/post_disable
methods, causing fimd_dp_clock_enable() to be called
before the FIMD device was activated. To fix this,
runtime PM guards were added to fimd_dp_clock_enable()
to ensure proper operation even when CRTC is not enabled.
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Merge tag 'exynos-drm-fixes-for-v6.16-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/daeinki/drm-exynos into drm-fixes
Fixups
- Fixed raw pointer leakage and unsafe behavior in printk()
. Switch from %pK to %p for pointer formatting, as %p is now safer
and prevents issues like raw pointer leakage and acquiring sleeping
locks in atomic contexts.
- Fixed kernel panic during boot
. A NULL pointer dereference issue occasionally occurred
when the vblank interrupt handler was called before
the DRM driver was fully initialized during boot.
So this patch fixes the issue by adding a check in the interrupt handler
to ensure the DRM driver is properly initialized.
- Fixed a lockup issue on Samsung Peach-Pit/Pi Chromebooks
. The issue occurred after commit c9b1150a68 changed
the call order of CRTC enable/disable and bridge pre_enable/post_disable
methods, causing fimd_dp_clock_enable() to be called
before the FIMD device was activated. To fix this,
runtime PM guards were added to fimd_dp_clock_enable()
to ensure proper operation even when CRTC is not enabled.
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Inki Dae <inki.dae@samsung.com>
Link: https://lore.kernel.org/r/20250629083554.28628-1-inki.dae@samsung.com
- Make mei interrupt top half irq disabled to fix RT builds
- Fix timeline left held on VMA alloc error
- Fix NULL pointer deref in vlv_dphy_param_init()
- Fix selftest mock_request() to avoid NULL deref
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://lore.kernel.org/r/aGYVPAA4KvsZqDFx@jlahtine-mobl
I2C adapters have their own timeout value which can be changed by
userspace if desired. Use it for I2C transfers. The default is 1Hz, so
the default behaviour is unchanged.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20250604101831.56585-5-wsa+renesas@sang-engineering.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
I2C adapters have their own timeout value which can be changed by
userspace if desired. Use it for I2C transfers. The default is 1Hz, so
the default behaviour is unchanged.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20250604101831.56585-4-wsa+renesas@sang-engineering.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
I2C adapters have their own timeout value which can be changed by
userspace if desired. Use it for I2C transfers. The default is 1Hz, so
the default behaviour is unchanged.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20250604101831.56585-3-wsa+renesas@sang-engineering.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
I2C adapters have their own timeout value which can be changed by
userspace if desired. Use it for I2C transfers. The default is 1Hz, so
the default behaviour is unchanged.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20250604101831.56585-2-wsa+renesas@sang-engineering.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
In drm::Device::new() we allocate with __drm_dev_alloc() and return an
ARef<drm::Device>.
When the reference count of the drm::Device falls to zero, the C code
automatically calls drm_dev_release(), which eventually frees the memory
allocated in drm::Device::new().
However, due to that, drm::Device::drop() is never called. As a result
the destructor of the user's private data, i.e. drm::Device::data is
never called. Hence, fix this by calling drop_in_place() from the DRM
device's release callback.
Fixes: 1e4b8896c0 ("rust: drm: add device abstraction")
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250629153747.72536-1-dakr@kernel.org
soc-button-array hardcodes a debounce value by means of gpio_keys
which uses pinctrl-amd as a backend to program debounce for a GPIO.
This hardcoded value doesn't match what the firmware intended to be
programmed in _AEI. The hardcoded debounce leads to problems waking
from suspend. There isn't appetite to conditionalize the behavior in
soc-button-array or gpio-keys so clear it when the system suspends to
avoid problems with being able to resume.
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Hans de Goede <hansg@kernel.org>
Fixes: 5c4fa2a6da ("Input: soc_button_array - debounce the buttons")
Link: https://lore.kernel.org/linux-input/mkgtrb5gt7miyg6kvqdlbu4nj3elym6ijudobpdi26gp4xxay5@rsa6ytrjvj2q/
Link: https://lore.kernel.org/linux-input/20250625215813.3477840-1-superm1@kernel.org/
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Hans de Goede <hansg@kernel.org>
Link: https://lore.kernel.org/20250627150155.3311574-1-superm1@kernel.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
- Use the new GPIO line value setter callbacks,
- Validate pins before setting a mux function on RZ/G2L.
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Merge tag 'renesas-pinctrl-for-v6.17-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers into devel
pinctrl: renesas: Updates for v6.17
- Use the new GPIO line value setter callbacks,
- Validate pins before setting a mux function on RZ/G2L.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This fixes a bunch of command hangs after runtime suspend/resume.
This fixes a regression caused by code movement in the commit below,
the commit seems to just change timings enough to cause this to happen
now, and adding the sleep seems to avoid it.
I've spent some time trying to root cause it to no great avail,
it seems like a bug on the firmware side, but it could be a bug
in our rpc handling that I can't find.
Either way, we should land the workaround to fix the problem,
while we continue to work out the root cause.
Signed-off-by: Dave Airlie <airlied@redhat.com>
Cc: Ben Skeggs <bskeggs@nvidia.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Fixes: c21b039715 ("drm/nouveau/gsp: add hals for fbsr.suspend/resume()")
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250702232707.175679-1-airlied@gmail.com