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Linux kernel ============ The Linux kernel is the core of any Linux operating system. It manages hardware, system resources, and provides the fundamental services for all other software. Quick Start ----------- * Report a bug: See Documentation/admin-guide/reporting-issues.rst * Get the latest kernel: https://kernel.org * Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst * Join the community: https://lore.kernel.org/ Essential Documentation ----------------------- All users should be familiar with: * Building requirements: Documentation/process/changes.rst * Code of Conduct: Documentation/process/code-of-conduct.rst * License: See COPYING Documentation can be built with make htmldocs or viewed online at: https://www.kernel.org/doc/html/latest/ Who Are You? ============ Find your role below: * New Kernel Developer - Getting started with kernel development * Academic Researcher - Studying kernel internals and architecture * Security Expert - Hardening and vulnerability analysis * Backport/Maintenance Engineer - Maintaining stable kernels * System Administrator - Configuring and troubleshooting * Maintainer - Leading subsystems and reviewing patches * Hardware Vendor - Writing drivers for new hardware * Distribution Maintainer - Packaging kernels for distros For Specific Users ================== New Kernel Developer -------------------- Welcome! Start your kernel development journey here: * Getting Started: Documentation/process/development-process.rst * Your First Patch: Documentation/process/submitting-patches.rst * Coding Style: Documentation/process/coding-style.rst * Build System: Documentation/kbuild/index.rst * Development Tools: Documentation/dev-tools/index.rst * Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst * Core APIs: Documentation/core-api/index.rst Academic Researcher ------------------- Explore the kernel's architecture and internals: * Researcher Guidelines: Documentation/process/researcher-guidelines.rst * Memory Management: Documentation/mm/index.rst * Scheduler: Documentation/scheduler/index.rst * Networking Stack: Documentation/networking/index.rst * Filesystems: Documentation/filesystems/index.rst * RCU (Read-Copy Update): Documentation/RCU/index.rst * Locking Primitives: Documentation/locking/index.rst * Power Management: Documentation/power/index.rst Security Expert --------------- Security documentation and hardening guides: * Security Documentation: Documentation/security/index.rst * LSM Development: Documentation/security/lsm-development.rst * Self Protection: Documentation/security/self-protection.rst * Reporting Vulnerabilities: Documentation/process/security-bugs.rst * CVE Procedures: Documentation/process/cve.rst * Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst * Security Features: Documentation/userspace-api/seccomp_filter.rst Backport/Maintenance Engineer ----------------------------- Maintain and stabilize kernel versions: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * Backporting Guide: Documentation/process/backporting.rst * Applying Patches: Documentation/process/applying-patches.rst * Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git for Maintainers: Documentation/maintainer/configure-git.rst System Administrator -------------------- Configure, tune, and troubleshoot Linux systems: * Admin Guide: Documentation/admin-guide/index.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst * Tracing/Debugging: Documentation/trace/index.rst * Performance Security: Documentation/admin-guide/perf-security.rst * Hardware Monitoring: Documentation/hwmon/index.rst Maintainer ---------- Lead kernel subsystems and manage contributions: * Maintainer Handbook: Documentation/maintainer/index.rst * Pull Requests: Documentation/maintainer/pull-requests.rst * Managing Patches: Documentation/maintainer/modifying-patches.rst * Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst * Development Process: Documentation/process/maintainer-handbooks.rst * Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git Configuration: Documentation/maintainer/configure-git.rst Hardware Vendor --------------- Write drivers and support new hardware: * Driver API Guide: Documentation/driver-api/index.rst * Driver Model: Documentation/driver-api/driver-model/driver.rst * Device Drivers: Documentation/driver-api/infrastructure.rst * Bus Types: Documentation/driver-api/driver-model/bus.rst * Device Tree Bindings: Documentation/devicetree/bindings/ * Power Management: Documentation/driver-api/pm/index.rst * DMA API: Documentation/core-api/dma-api.rst Distribution Maintainer ----------------------- Package and distribute the kernel: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * ABI Documentation: Documentation/ABI/README * Kernel Configuration: Documentation/kbuild/kconfig.rst * Module Signing: Documentation/admin-guide/module-signing.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst Communication and Support ========================= * Mailing Lists: https://lore.kernel.org/ * IRC: #kernelnewbies on irc.oftc.net * Bugzilla: https://bugzilla.kernel.org/ * MAINTAINERS file: Lists subsystem maintainers and mailing lists * Email Clients: Documentation/process/email-clients.rst
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Fedora QA reported the following panic:
BUG: unable to handle page fault for address: 0000000040003e54
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS edk2-20251119-3.fc43 11/19/2025
RIP: 0010:vmware_hypercall4.constprop.0+0x52/0x90
..
Call Trace:
vmmouse_report_events+0x13e/0x1b0
psmouse_handle_byte+0x15/0x60
ps2_interrupt+0x8a/0xd0
...
because the QEMU VMware mouse emulation is buggy, and clears the top 32
bits of %rdi that the kernel kept a pointer in.
The QEMU vmmouse driver saves and restores the register state in a
"uint32_t data[6];" and as a result restores the state with the high
bits all cleared.
RDI originally contained the value of a valid kernel stack address
(0xff5eeb3240003e54). After the vmware hypercall it now contains
0x40003e54, and we get a page fault as a result when it is dereferenced.
The proper fix would be in QEMU, but this works around the issue in the
kernel to keep old setups working, when old kernels had not happened to
keep any state in %rdi over the hypercall.
In theory this same issue exists for all the hypercalls in the vmmouse
driver; in practice it has only been seen with vmware_hypercall3() and
vmware_hypercall4(). For now, just mark RDI/RSI as clobbered for those
two calls. This should have a minimal effect on code generation overall
as it should be rare for the compiler to want to make RDI/RSI live
across hypercalls.
Reported-by: Justin Forbes <jforbes@fedoraproject.org>
Link: https://lore.kernel.org/all/99a9c69a-fc1a-43b7-8d1e-c42d6493b41f@broadcom.com/
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull hotfixes from Andrew Morton:
"A couple of late-breaking MM fixes. One against a new-in-this-cycle
patch and the other addresses a locking issue which has been there for
over a year"
* tag 'mm-hotfixes-stable-2026-02-06-12-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
mm/memory-failure: reject unsupported non-folio compound page
procfs: avoid fetching build ID while holding VMA lock
Pull tracing fix from Steven Rostedt:
- Fix event format field alignments for 32 bit architectures
The fields in the event format files are used to parse the raw binary
buffer data by applications. If they are incorrect, then the
application produces garbage.
On 32 bit architectures, the function graph 64bit calltime and
rettime were off by 4bytes. That's because the actual fields are in a
packed structure but the macros used by the ftrace events did not
mark them as packed, and instead, gave them their natural alignment
which made their offsets off by 4 bytes.
There are macros to have a packed field within an embedded structure
of an event, but there's no macro for normal fields within a packed
structure of the event. The macro __field_packed() was used for the
packed embedded structure field. Rename that to __field_desc_packed()
(to match the non-packed embedded field macro __field_desc()), and
make __field_packed() for fields that are in a packed event structure
(which matches the unpacked __field() macro).
Switch the calltime and rettime fields of the function graph event to
use the new __field_packed() and this makes the offsets correct.
* tag 'trace-v6.19-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Fix ftrace event field alignments
When !CONFIG_TRANSPARENT_HUGEPAGE, a non-folio compound page can appear in
a userspace mapping via either vm_insert_*() functions or
vm_operatios_struct->fault(). They are not folios, thus should not be
considered for folio operations like split. To reject these pages, make
sure get_hwpoison_page() is always called as HWPoisonHandlable() will do
the right work.
[Some commit log borrowed from Zi Yan. Thanks.]
Link: https://lkml.kernel.org/r/20260205075328.523211-1-linmiaohe@huawei.com
Fixes: 689b8986776c ("mm/memory-failure: improve large block size folio handling")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reported-by: 是参差 <shicenci@gmail.com>
Closes: https://lore.kernel.org/all/PS1PPF7E1D7501F1E4F4441E7ECD056DEADAB98A@PS1PPF7E1D7501F.apcprd02.prod.outlook.com/
Reviewed-by: Zi Yan <ziy@nvidia.com>
Tested-by: Zi Yan <ziy@nvidia.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull ceph fixes from Ilya Dryomov:
"One RBD and two CephFS fixes which address potential oopses.
The RBD thing is more of a rare edge case that pops up in our CI,
while the two CephFS scenarios are regressions that were reported by
users and can be triggered trivially in normal operation. All marked
for stable"
* tag 'ceph-for-6.19-rc9' of https://github.com/ceph/ceph-client:
ceph: fix NULL pointer dereference in ceph_mds_auth_match()
ceph: fix oops due to invalid pointer for kfree() in parse_longname()
rbd: check for EOD after exclusive lock is ensured to be held
The fields of ftrace specific events (events used to save ftrace internal
events like function traces and trace_printk) are generated similarly to
how normal trace event fields are generated. That is, the fields are added
to a trace_events_fields array that saves the name, offset, size,
alignment and signness of the field. It is used to produce the output in
the format file in tracefs so that tooling knows how to parse the binary
data of the trace events.
The issue is that some of the ftrace event structures are packed. The
function graph exit event structures are one of them. The 64 bit calltime
and rettime fields end up 4 byte aligned, but the algorithm to show to
userspace shows them as 8 byte aligned.
The macros that create the ftrace events has one for embedded structure
fields. There's two macros for theses fields:
__field_desc() and __field_packed()
The difference of the latter macro is that it treats the field as packed.
Rename that field to __field_desc_packed() and create replace the
__field_packed() to be a normal field that is packed and have the calltime
and rettime use those.
This showed up on 32bit architectures for function graph time fields. It
had:
~# cat /sys/kernel/tracing/events/ftrace/funcgraph_exit/format
[..]
field:unsigned long func; offset:8; size:4; signed:0;
field:unsigned int depth; offset:12; size:4; signed:0;
field:unsigned int overrun; offset:16; size:4; signed:0;
field:unsigned long long calltime; offset:24; size:8; signed:0;
field:unsigned long long rettime; offset:32; size:8; signed:0;
Notice that overrun is at offset 16 with size 4, where in the structure
calltime is at offset 20 (16 + 4), but it shows the offset at 24. That's
because it used the alignment of unsigned long long when used as a
declaration and not as a member of a structure where it would be aligned
by word size (in this case 4).
By using the proper structure alignment, the format has it at the correct
offset:
~# cat /sys/kernel/tracing/events/ftrace/funcgraph_exit/format
[..]
field:unsigned long func; offset:8; size:4; signed:0;
field:unsigned int depth; offset:12; size:4; signed:0;
field:unsigned int overrun; offset:16; size:4; signed:0;
field:unsigned long long calltime; offset:20; size:8; signed:0;
field:unsigned long long rettime; offset:28; size:8; signed:0;
Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reported-by: "jempty.liang" <imntjempty@163.com>
Link: https://patch.msgid.link/20260204113628.53faec78@gandalf.local.home
Fixes: 04ae87a52074e ("ftrace: Rework event_create_dir()")
Closes: https://lore.kernel.org/all/20260130015740.212343-1-imntjempty@163.com/
Closes: https://lore.kernel.org/all/20260202123342.2544795-1-imntjempty@163.com/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Fix PROCMAP_QUERY to fetch optional build ID only after dropping mmap_lock
or per-VMA lock, whichever was used to lock VMA under question, to avoid
deadlock reported by syzbot:
-> #1 (&mm->mmap_lock){++++}-{4:4}:
__might_fault+0xed/0x170
_copy_to_iter+0x118/0x1720
copy_page_to_iter+0x12d/0x1e0
filemap_read+0x720/0x10a0
blkdev_read_iter+0x2b5/0x4e0
vfs_read+0x7f4/0xae0
ksys_read+0x12a/0x250
do_syscall_64+0xcb/0xf80
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&sb->s_type->i_mutex_key#8){++++}-{4:4}:
__lock_acquire+0x1509/0x26d0
lock_acquire+0x185/0x340
down_read+0x98/0x490
blkdev_read_iter+0x2a7/0x4e0
__kernel_read+0x39a/0xa90
freader_fetch+0x1d5/0xa80
__build_id_parse.isra.0+0xea/0x6a0
do_procmap_query+0xd75/0x1050
procfs_procmap_ioctl+0x7a/0xb0
__x64_sys_ioctl+0x18e/0x210
do_syscall_64+0xcb/0xf80
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
rlock(&mm->mmap_lock);
lock(&sb->s_type->i_mutex_key#8);
lock(&mm->mmap_lock);
rlock(&sb->s_type->i_mutex_key#8);
*** DEADLOCK ***
This seems to be exacerbated (as we haven't seen these syzbot reports
before that) by the recent:
777a8560fd29 ("lib/buildid: use __kernel_read() for sleepable context")
To make this safe, we need to grab file refcount while VMA is still locked, but
other than that everything is pretty straightforward. Internal build_id_parse()
API assumes VMA is passed, but it only needs the underlying file reference, so
just add another variant build_id_parse_file() that expects file passed
directly.
[akpm@linux-foundation.org: fix up kerneldoc]
Link: https://lkml.kernel.org/r/20260129215340.3742283-1-andrii@kernel.org
Fixes: ed5d583a88a9 ("fs/procfs: implement efficient VMA querying API for /proc/<pid>/maps")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reported-by: <syzbot+4e70c8e0a2017b432f7a@syzkaller.appspotmail.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Tested-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Song Liu <song@kernel.org>
Cc: Stanislav Fomichev <sdf@fomichev.me>
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull dma-mapping fixes from Marek Szyprowski:
"Two minor fixes for the DMA-mapping subsystem:
- check for the rare case of the allocation failure of the global CMA
pool (Shanker Donthineni)
- avoid perf buffer overflow when tracing large scatter-gather lists
(Deepanshu Kartikey)"
* tag 'dma-mapping-6.19-2026-02-06' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux:
dma: contiguous: Check return value of dma_contiguous_reserve_area()
tracing/dma: Cap dma_map_sg tracepoint arrays to prevent buffer overflow
The CephFS kernel client has regression starting from 6.18-rc1.
We have issue in ceph_mds_auth_match() if fs_name == NULL:
const char fs_name = mdsc->fsc->mount_options->mds_namespace;
...
if (auth->match.fs_name && strcmp(auth->match.fs_name, fs_name)) {
/ fsname mismatch, try next one */
return 0;
}
Patrick Donnelly suggested that: In summary, we should definitely start
decoding `fs_name` from the MDSMap and do strict authorizations checks
against it. Note that the `-o mds_namespace=foo` should only be used for
selecting the file system to mount and nothing else. It's possible
no mds_namespace is specified but the kernel will mount the only
file system that exists which may have name "foo".
This patch reworks ceph_mdsmap_decode() and namespace_equals() with
the goal of supporting the suggested concept. Now struct ceph_mdsmap
contains m_fs_name field that receives copy of extracted FS name
by ceph_extract_encoded_string(). For the case of "old" CephFS file
systems, it is used "cephfs" name.
[ idryomov: replace redundant %*pE with %s in ceph_mdsmap_decode(),
get rid of a series of strlen() calls in ceph_namespace_match(),
drop changes to namespace_equals() body to avoid treating empty
mds_namespace as equal, drop changes to ceph_mdsc_handle_fsmap()
as namespace_equals() isn't an equivalent substitution there ]
Cc: stable@vger.kernel.org
Fixes: 22c73d52a6d0 ("ceph: fix multifs mds auth caps issue")
Link: https://tracker.ceph.com/issues/73886
Signed-off-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Reviewed-by: Patrick Donnelly <pdonnell@ibm.com>
Tested-by: Patrick Donnelly <pdonnell@ibm.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
When realloc() fails in add_string(), the function returns -1 but leaves
*vals pointing to the previously allocated memory. This can cause memory
leaks in callers like make_trace_array() that return on error without
freeing the partially built array.
Fix this by freeing *vals and setting it to NULL when realloc() fails.
This makes the error handling self-contained in add_string() so callers
don't need to handle cleanup on failure.
This bug is found by my static analysis tool and my code review.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: e30f8e61e2518 ("tracing: Add a tracepoint verification check at build time")
Link: https://patch.msgid.link/20260119114542.1714405-1-geoffreyhe2@gmail.com
Signed-off-by: Weigang He <geoffreyhe2@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
liveupdate is used to enable Live Update Orchestrator (LUO) early during
boot. Add it to kernel-parameters.txt so users can discover and use it.
Link: https://lkml.kernel.org/r/20260130112036.359806-1-me@linux.beauty
Signed-off-by: Li Chen <me@linux.beauty>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Frank van der Linden <fvdl@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kees Cook <kees@kernel.org>
Cc: Li RongQing <lirongqing@baidu.com>
Cc: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Pratyush Yadav <ptyadav@amazon.de>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull iommu fix from Joerg Roedel:
- Fix wrong definition of PASID_FLAG_PWSNP bit. This caused DMAR errors
on Arrow Lake platforms.
* tag 'iommu-fix-v6.19-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux:
iommu/vt-d: Treat PAGE_SNOOP and PWSNP separately
Commit 8f1fc1bf1a3d ("dma: contiguous: Reserve default CMA heap")
introduced a bug where dma_heap_cma_register_heap() is called with
a NULL pointer when dma_contiguous_reserve_area() fails to reserve
the CMA area.
When dma_contiguous_reserve_area() fails, dma_contiguous_default_area
remains NULL (initialized as a global variable), but the code doesn't
check the return value and proceeds to call dma_heap_cma_register_heap()
with this NULL pointer.
Later during boot, add_cma_heaps() iterates through the dma_areas[]
array and attempts to register heaps. When it encounters the NULL
pointer stored by the earlier call, it crashes in __add_cma_heap()
-> dma_heap_add() when trying to dereference the NULL CMA pointer.
The crash manifests as:
Unable to handle kernel NULL pointer dereference at virtual address
0000000000000038
...
Call trace:
dma_heap_add+0x40/0x2b0
__add_cma_heap+0x80/0xe0
add_cma_heaps+0x64/0xb0
do_one_initcall+0x60/0x318
kernel_init_freeable+0x260/0x2f0
kernel_init+0x2c/0x168
ret_from_fork+0x10/0x20
Fix this by checking the return value of dma_contiguous_reserve_area()
and only calling dma_heap_cma_register_heap() when the reservation
succeeds.
Fixes: 8f1fc1bf1a3d ("dma: contiguous: Reserve default CMA heap")
Signed-off-by: Shanker Donthineni <sdonthineni@nvidia.com>
Reviewed-by: T.J. Mercier <tjmercier@google.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260129181317.2429196-1-sdonthineni@nvidia.com
This fixes a kernel oops when reading ceph snapshot directories (.snap),
for example by simply running `ls /mnt/my_ceph/.snap`.
The variable str is guarded by __free(kfree), but advanced by one for
skipping the initial '_' in snapshot names. Thus, kfree() is called
with an invalid pointer. This patch removes the need for advancing the
pointer so kfree() is called with correct memory pointer.
Steps to reproduce:
1. Create snapshots on a cephfs volume (I've 63 snaps in my testcase)
2. Add cephfs mount to fstab
$ echo "samba-fileserver@.files=/volumes/datapool/stuff/3461082b-ecc9-4e82-8549-3fd2590d3fb6 /mnt/test/stuff ceph acl,noatime,_netdev 0 0" >> /etc/fstab
3. Reboot the system
$ systemctl reboot
4. Check if it's really mounted
$ mount | grep stuff
5. List snapshots (expected 63 snapshots on my system)
$ ls /mnt/test/stuff/.snap
Now ls hangs forever and the kernel log shows the oops.
Cc: stable@vger.kernel.org
Fixes: 101841c38346 ("[ceph] parse_longname(): strrchr() expects NUL-terminated string")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220807
Suggested-by: Helge Deller <deller@gmx.de>
Signed-off-by: Daniel Vogelbacher <daniel@chaospixel.com>
Reviewed-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
When funcgraph-args and funcgraph-retaddr are both enabled, many kernel
functions display invalid parameters in trace logs.
The issue occurs because print_graph_retval() passes a mismatched args
pointer to print_function_args(). Fix this by retrieving the correct
args pointer using the FGRAPH_ENTRY_ARGS() macro.
Link: https://patch.msgid.link/20260112021601.1300479-1-dolinux.peng@gmail.com
Fixes: f83ac7544fbf ("function_graph: Enable funcgraph-args and funcgraph-retaddr to work simultaneously")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
When truncating a large swap entry, shmem_free_swap() returns 0 when the
entry's index doesn't match the given index due to lookup alignment. The
failure fallback path checks if the entry crosses the end border and
aborts when it happens, so truncate won't erase an unexpected entry or
range. But one scenario was ignored.
When `index` points to the middle of a large swap entry, and the large
swap entry doesn't go across the end border, find_get_entries() will
return that large swap entry as the first item in the batch with
`indices[0]` equal to `index`. The entry's base index will be smaller
than `indices[0]`, so shmem_free_swap() will fail and return 0 due to the
"base < index" check. The code will then call shmem_confirm_swap(), get
the order, check if it crosses the END boundary (which it doesn't), and
retry with the same index.
The next iteration will find the same entry again at the same index with
same indices, leading to an infinite loop.
Fix this by retrying with a round-down index, and abort if the index is
smaller than the truncate range.
Link: https://lkml.kernel.org/r/aXo6ltB5iqAKJzY8@KASONG-MC4
Fixes: 809bc86517cc ("mm: shmem: support large folio swap out")
Fixes: 8a1968bd997f ("mm/shmem, swap: fix race of truncate and swap entry split")
Signed-off-by: Kairui Song <kasong@tencent.com>
Reported-by: Chris Mason <clm@meta.com>
Closes: https://lore.kernel.org/linux-mm/20260128130336.727049-1-clm@meta.com/
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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