Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
Clone this repository
For self-hosted knots, clone URLs may differ based on your setup.
Download tar.gz
Pull tpm fixes from Jarkko Sakkinen:
"This fixes two unaddressed review comments for the HMAC encryption
patch set. They are cosmetic but we are better off, if such
unnecessary glitches do not exist in the release.
The important part is enabling the HMAC encryption by default only on
x86-64 because that is the only sufficiently tested arch.
Finally, there is a bug fix for SPI transfer buffer allocation, which
did not take into account the SPI header size"
* tag 'tpmdd-next-6.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd:
tpm: Enable TCG_TPM2_HMAC by default only for X86_64
tpm: Rename TPM2_OA_TMPL to TPM2_OA_NULL_KEY and make it local
tpm: Open code tpm_buf_parameters()
tpm_tis_spi: Account for SPI header when allocating TPM SPI xfer buffer
Pull probes fixes from Masami Hiramatsu:
- uprobes: prevent mutex_lock() under rcu_read_lock().
Recent changes moved uprobe_cpu_buffer preparation which involves
mutex_lock(), under __uprobe_trace_func() which is called inside
rcu_read_lock().
Fix it by moving uprobe_cpu_buffer preparation outside of
__uprobe_trace_func()
- kprobe-events: handle the error case of btf_find_struct_member()
* tag 'probes-fixes-v6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing/probes: fix error check in parse_btf_field()
uprobes: prevent mutex_lock() under rcu_read_lock()
Given the not fully root caused performance issues on non-x86 platforms,
enable the feature by default only for x86-64. That is the platform it
brings the most value and has gone most of the QA. Can be reconsidered
later and can be obviously opt-in enabled too on any arch.
Link: https://lore.kernel.org/linux-integrity/bf67346ef623ff3c452c4f968b7d900911e250c3.camel@gmail.com/#t
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Pull pmdomain fix from Ulf Hansson:
- Fix regression in gpcv2 PM domain for i.MX8
* tag 'pmdomain-v6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/linux-pm:
pmdomain: imx: gpcv2: Add delay after power up handshake
btf_find_struct_member() might return NULL or an error via the
ERR_PTR() macro. However, its caller in parse_btf_field() only checks
for the NULL condition. Fix this by using IS_ERR() and returning the
error up the stack.
Link: https://lore.kernel.org/all/20240527094351.15687-1-clopez@suse.de/
Fixes: c440adfbe3025 ("tracing/probes: Support BTF based data structure field access")
Signed-off-by: Carlos López <clopez@suse.de>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Rename and document TPM2_OA_TMPL, as originally requested in the patch
set review, but left unaddressed without any appropriate reasoning. The
new name is TPM2_OA_NULL_KEY, has a documentation and is local only to
tpm2-sessions.c.
Link: https://lore.kernel.org/linux-integrity/ddbeb8111f48a8ddb0b8fca248dff6cc9d7079b2.camel@HansenPartnership.com/
Link: https://lore.kernel.org/linux-integrity/CZCKTWU6ZCC9.2UTEQPEVICYHL@suppilovahvero/
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Pull vfs fixes from Christian Brauner:
- Fix io_uring based write-through after converting cifs to use the
netfs library
- Fix aio error handling when doing write-through via netfs library
- Fix performance regression in iomap when used with non-large folio
mappings
- Fix signalfd error code
- Remove obsolete comment in signalfd code
- Fix async request indication in netfs_perform_write() by raising
BDP_ASYNC when IOCB_NOWAIT is set
- Yield swap device immediately to prevent spurious EBUSY errors
- Don't cross a .backup mountpoint from backup volumes in afs to avoid
infinite loops
- Fix a race between umount and async request completion in 9p after 9p
was converted to use the netfs library
* tag 'vfs-6.10-rc2.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
netfs, 9p: Fix race between umount and async request completion
afs: Don't cross .backup mountpoint from backup volume
swap: yield device immediately
netfs: Fix setting of BDP_ASYNC from iocb flags
signalfd: drop an obsolete comment
signalfd: fix error return code
iomap: fault in smaller chunks for non-large folio mappings
filemap: add helper mapping_max_folio_size()
netfs: Fix AIO error handling when doing write-through
netfs: Fix io_uring based write-through
AudioMix BLK-CTRL on i.MX8MP encountered an accessing register issue
after power up.
[ 2.181035] Kernel panic - not syncing: Asynchronous SError Interrupt
[ 2.181038] CPU: 1 PID: 48 Comm: kworker/u16:2 Not tainted 6.9.0-rc5-next-20240424-00003-g21cec88845c6 #171
[ 2.181047] Hardware name: NXP i.MX8MPlus EVK board (DT)
[ 2.181050] Workqueue: events_unbound deferred_probe_work_func
[ 2.181064] Call trace:
[...]
[ 2.181142] arm64_serror_panic+0x6c/0x78
[ 2.181149] do_serror+0x3c/0x70
[ 2.181157] el1h_64_error_handler+0x30/0x48
[ 2.181164] el1h_64_error+0x64/0x68
[ 2.181171] clk_imx8mp_audiomix_runtime_resume+0x34/0x44
[ 2.181183] __genpd_runtime_resume+0x30/0x80
[ 2.181195] genpd_runtime_resume+0x110/0x244
[ 2.181205] __rpm_callback+0x48/0x1d8
[ 2.181213] rpm_callback+0x68/0x74
[ 2.181224] rpm_resume+0x468/0x6c0
[ 2.181234] __pm_runtime_resume+0x50/0x94
[ 2.181243] pm_runtime_get_suppliers+0x60/0x8c
[ 2.181258] __driver_probe_device+0x48/0x12c
[ 2.181268] driver_probe_device+0xd8/0x15c
[ 2.181278] __device_attach_driver+0xb8/0x134
[ 2.181290] bus_for_each_drv+0x84/0xe0
[ 2.181302] __device_attach+0x9c/0x188
[ 2.181312] device_initial_probe+0x14/0x20
[ 2.181323] bus_probe_device+0xac/0xb0
[ 2.181334] deferred_probe_work_func+0x88/0xc0
[ 2.181344] process_one_work+0x150/0x290
[ 2.181357] worker_thread+0x2f8/0x408
[ 2.181370] kthread+0x110/0x114
[ 2.181381] ret_from_fork+0x10/0x20
[ 2.181391] SMP: stopping secondary CPUs
According to comments in power up handshake:
/* request the ADB400 to power up */
if (domain->bits.hskreq) {
regmap_update_bits(domain->regmap, domain->regs->hsk,
domain->bits.hskreq, domain->bits.hskreq);
/*
* ret = regmap_read_poll_timeout(domain->regmap, domain->regs->hsk, reg_val,
* (reg_val & domain->bits.hskack), 0,
* USEC_PER_MSEC);
* Technically we need the commented code to wait handshake. But that needs
* the BLK-CTL module BUS clk-en bit being set.
*
* There is a separate BLK-CTL module and we will have such a driver for it,
* that driver will set the BUS clk-en bit and handshake will be triggered
* automatically there. Just add a delay and suppose the handshake finish
* after that.
*/
}
The BLK-CTL module needs to add delay to wait for a handshake request finished.
For some BLK-CTL module (eg. AudioMix on i.MX8MP) doesn't have BUS clk-en
bit, it is better to add delay in this driver, as the BLK-CTL module doesn't
need to care about how it is powered up.
regmap_read_bypassed() is to make sure the above write IO transaction already
reaches target before udelay().
Fixes: 1496dd413b2e ("clk: imx: imx8mp: Add pm_runtime support for power saving")
Reported-by: Francesco Dolcini <francesco@dolcini.it>
Closes: https://lore.kernel.org/all/66293535.170a0220.21fe.a2e7@mx.google.com/
Suggested-by: Frank Li <frank.li@nxp.com>
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Tested-by: Adam Ford <aford173@gmail.com>
Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Link: https://lore.kernel.org/r/1715396125-3724-1-git-send-email-shengjiu.wang@nxp.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Recent changes made uprobe_cpu_buffer preparation lazy, and moved it
deeper into __uprobe_trace_func(). This is problematic because
__uprobe_trace_func() is called inside rcu_read_lock()/rcu_read_unlock()
block, which then calls prepare_uprobe_buffer() -> uprobe_buffer_get() ->
mutex_lock(&ucb->mutex), leading to a splat about using mutex under
non-sleepable RCU:
BUG: sleeping function called from invalid context at kernel/locking/mutex.c:585
in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 98231, name: stress-ng-sigq
preempt_count: 0, expected: 0
RCU nest depth: 1, expected: 0
...
Call Trace:
<TASK>
dump_stack_lvl+0x3d/0xe0
__might_resched+0x24c/0x270
? prepare_uprobe_buffer+0xd5/0x1d0
__mutex_lock+0x41/0x820
? ___perf_sw_event+0x206/0x290
? __perf_event_task_sched_in+0x54/0x660
? __perf_event_task_sched_in+0x54/0x660
prepare_uprobe_buffer+0xd5/0x1d0
__uprobe_trace_func+0x4a/0x140
uprobe_dispatcher+0x135/0x280
? uprobe_dispatcher+0x94/0x280
uprobe_notify_resume+0x650/0xec0
? atomic_notifier_call_chain+0x21/0x110
? atomic_notifier_call_chain+0xf8/0x110
irqentry_exit_to_user_mode+0xe2/0x1e0
asm_exc_int3+0x35/0x40
RIP: 0033:0x7f7e1d4da390
Code: 33 04 00 0f 1f 80 00 00 00 00 f3 0f 1e fa b9 01 00 00 00 e9 b2 fc ff ff 66 90 f3 0f 1e fa 31 c9 e9 a5 fc ff ff 0f 1f 44 00 00 <cc> 0f 1e fa b8 27 00 00 00 0f 05 c3 0f 1f 40 00 f3 0f 1e fa b8 6e
RSP: 002b:00007ffd2abc3608 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000076d325f1 RCX: 0000000000000000
RDX: 0000000076d325f1 RSI: 000000000000000a RDI: 00007ffd2abc3690
RBP: 000000000000000a R08: 00017fb700000000 R09: 00017fb700000000
R10: 00017fb700000000 R11: 0000000000000246 R12: 0000000000017ff2
R13: 00007ffd2abc3610 R14: 0000000000000000 R15: 00007ffd2abc3780
</TASK>
Luckily, it's easy to fix by moving prepare_uprobe_buffer() to be called
slightly earlier: into uprobe_trace_func() and uretprobe_trace_func(), outside
of RCU locked section. This still keeps this buffer preparation lazy and helps
avoid the overhead when it's not needed. E.g., if there is only BPF uprobe
handler installed on a given uprobe, buffer won't be initialized.
Note, the other user of prepare_uprobe_buffer(), __uprobe_perf_func(), is not
affected, as it doesn't prepare buffer under RCU read lock.
Link: https://lore.kernel.org/all/20240521053017.3708530-1-andrii@kernel.org/
Fixes: 1b8f85defbc8 ("uprobes: prepare uprobe args buffer lazily")
Reported-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
With only single call site, this makes no sense (slipped out of the
radar during the review). Open code and document the action directly
to the site, to make it more readable.
Fixes: 1b6d7f9eb150 ("tpm: add session encryption protection to tpm2_get_random()")
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
There's a problem in 9p's interaction with netfslib whereby a crash occurs
because the 9p_fid structs get forcibly destroyed during client teardown
(without paying attention to their refcounts) before netfslib has finished
with them. However, it's not a simple case of deferring the clunking that
p9_fid_put() does as that requires the p9_client record to still be
present.
The problem is that netfslib has to unlock pages and clear the IN_PROGRESS
flag before destroying the objects involved - including the fid - and, in
any case, nothing checks to see if writeback completed barring looking at
the page flags.
Fix this by keeping a count of outstanding I/O requests (of any type) and
waiting for it to quiesce during inode eviction.
Reported-by: syzbot+df038d463cca332e8414@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/0000000000005be0aa061846f8d6@google.com/
Reported-by: syzbot+d7c7a495a5e466c031b6@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/000000000000b86c5e06130da9c6@google.com/
Reported-by: syzbot+1527696d41a634cc1819@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/000000000000041f960618206d7e@google.com/
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/755891.1716560771@warthog.procyon.org.uk
Tested-by: syzbot+d7c7a495a5e466c031b6@syzkaller.appspotmail.com
Reviewed-by: Dominique Martinet <asmadeus@codewreck.org>
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: Steve French <sfrench@samba.org>
cc: Hillf Danton <hdanton@sina.com>
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Reported-and-tested-by: syzbot+d7c7a495a5e466c031b6@syzkaller.appspotmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
Pull coccinelle updates from Julia Lawall:
"One patch slightly improves the text in a comment.
The other patch (on minmax.cocci) removes a report about ? being used
in return statements that has been generating not very useful
suggestions to change idiomatic code"
* tag 'cocci-for-6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/jlawall/linux:
Coccinelle: pm_runtime: Fix grammar in comment
coccinelle: misc: minmax: Suppress reports for err returns
Pull NFS client updates from Trond Myklebust:
"Stable fixes:
- nfs: fix undefined behavior in nfs_block_bits()
- NFSv4.2: Fix READ_PLUS when server doesn't support OP_READ_PLUS
Bugfixes:
- Fix mixing of the lock/nolock and local_lock mount options
- NFSv4: Fixup smatch warning for ambiguous return
- NFSv3: Fix remount when using the legacy binary mount api
- SUNRPC: Fix the handling of expired RPCSEC_GSS contexts
- SUNRPC: fix the NFSACL RPC retries when soft mounts are enabled
- rpcrdma: fix handling for RDMA_CM_EVENT_DEVICE_REMOVAL
Features and cleanups:
- NFSv3: Use the atomic_open API to fix open(O_CREAT|O_TRUNC)
- pNFS/filelayout: S layout segment range in LAYOUTGET
- pNFS: rework pnfs_generic_pg_check_layout to check IO range
- NFSv2: Turn off enabling of NFS v2 by default"
* tag 'nfs-for-6.10-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
nfs: fix undefined behavior in nfs_block_bits()
pNFS: rework pnfs_generic_pg_check_layout to check IO range
pNFS/filelayout: check layout segment range
pNFS/filelayout: fixup pNfs allocation modes
rpcrdma: fix handling for RDMA_CM_EVENT_DEVICE_REMOVAL
NFS: Don't enable NFS v2 by default
NFS: Fix READ_PLUS when server doesn't support OP_READ_PLUS
sunrpc: fix NFSACL RPC retry on soft mount
SUNRPC: fix handling expired GSS context
nfs: keep server info for remounts
NFSv4: Fixup smatch warning for ambiguous return
NFS: make sure lock/nolock overriding local_lock mount option
NFS: add atomic_open for NFSv3 to handle O_TRUNC correctly.
pNFS/filelayout: Specify the layout segment range in LAYOUTGET
pNFS/filelayout: Remove the whole file layout requirement
The TPM SPI transfer mechanism uses MAX_SPI_FRAMESIZE for computing the
maximum transfer length and the size of the transfer buffer. As such, it
does not account for the 4 bytes of header that prepends the SPI data
frame. This can result in out-of-bounds accesses and was confirmed with
KASAN.
Introduce SPI_HDRSIZE to account for the header and use to allocate the
transfer buffer.
Fixes: a86a42ac2bd6 ("tpm_tis_spi: Add hardware wait polling")
Signed-off-by: Matthew R. Ochs <mochs@nvidia.com>
Tested-by: Carol Soto <csoto@nvidia.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>