Test scripts:
cd /sys/fs/cgroup/blkio/
echo "8:0 1024" > blkio.throttle.write_bps_device
echo $$ > cgroup.procs
dd if=/dev/zero of=/dev/sda bs=10k count=1 oflag=direct &
dd if=/dev/zero of=/dev/sda bs=10k count=1 oflag=direct &
Test result:
10240 bytes (10 kB, 10 KiB) copied, 10.0134 s, 1.0 kB/s
10240 bytes (10 kB, 10 KiB) copied, 10.0135 s, 1.0 kB/s
The problem is that the second bio is finished after 10s instead of 20s.
Root cause:
1) second bio will be flagged:
__blk_throtl_bio
while (true) {
...
if (sq->nr_queued[rw]) -> some bio is throttled already
break
};
bio_set_flag(bio, BIO_THROTTLED); -> flag the bio
2) flagged bio will be dispatched without waiting:
throtl_dispatch_tg
tg_may_dispatch
tg_with_in_bps_limit
if (bps_limit == U64_MAX || bio_flagged(bio, BIO_THROTTLED))
*wait = 0; -> wait time is zero
return true;
commit 9f5ede3c01 ("block: throttle split bio in case of iops limit")
support to count split bios for iops limit, thus it adds flagged bio
checking in tg_with_in_bps_limit() so that split bios will only count
once for bps limit, however, it introduce a new problem that io throttle
won't work if multiple bios are throttled.
In order to fix the problem, handle iops/bps limit in different ways:
1) for iops limit, there is no flag to record if the bio is throttled,
and iops is always applied.
2) for bps limit, original bio will be flagged with BIO_BPS_THROTTLED,
and io throttle will ignore bio with the flag.
Noted this patch also remove the code to set flag in __bio_clone(), it's
introduced in commit 111be88398 ("block-throttle: avoid double
charge"), and author thinks split bio can be resubmited and throttled
again, which is wrong because split bio will continue to dispatch from
caller.
Fixes: 9f5ede3c01 ("block: throttle split bio in case of iops limit")
Cc: <stable@vger.kernel.org>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220829022240.3348319-2-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Use atomic_long_try_cmpxchg instead of
atomic_long_cmpxchg (*ptr, old, new) == old in __sbitmap_queue_get_batch.
x86 CMPXCHG instruction returns success in ZF flag, so this change
saves a compare after cmpxchg (and related move instruction in front
of cmpxchg).
Also, atomic_long_cmpxchg implicitly assigns old *ptr value to "old"
when cmpxchg fails, enabling further code simplifications, e.g.
an extra memory read can be avoided in the loop.
No functional change intended.
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Link: https://lore.kernel.org/r/20220908151200.9993-1-ubizjak@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
syzbot reported hung task [1]. The following program is a simplified
version of the reproducer:
int main(void)
{
int sv[2], fd;
if (socketpair(AF_UNIX, SOCK_STREAM, 0, sv) < 0)
return 1;
if ((fd = open("/dev/nbd0", 0)) < 0)
return 1;
if (ioctl(fd, NBD_SET_SIZE_BLOCKS, 0x81) < 0)
return 1;
if (ioctl(fd, NBD_SET_SOCK, sv[0]) < 0)
return 1;
if (ioctl(fd, NBD_DO_IT) < 0)
return 1;
return 0;
}
When signal interrupt nbd_start_device_ioctl() waiting the condition
atomic_read(&config->recv_threads) == 0, the task can hung because it
waits the completion of the inflight IOs.
This patch fixes the issue by clearing queue, not just shutdown, when
signal interrupt nbd_start_device_ioctl().
Link: https://syzkaller.appspot.com/bug?id=7d89a3ffacd2b83fdd39549bc4d8e0a89ef21239 [1]
Reported-by: syzbot+38e6c55d4969a14c1534@syzkaller.appspotmail.com
Signed-off-by: Shigeru Yoshida <syoshida@redhat.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20220907163502.577561-1-syoshida@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When __sbq_wake_up() decrements wait_cnt to 0 but races with someone
else waking the waiter on the waitqueue (so the waitqueue becomes
empty), it exits without reseting wait_cnt to wake_batch number. Once
wait_cnt is 0, nobody will ever reset the wait_cnt or wake the new
waiters resulting in possible deadlocks or busyloops. Fix the problem by
making sure we reset wait_cnt even if we didn't wake up anybody in the
end.
Fixes: 040b83fcec ("sbitmap: fix possible io hung due to lost wakeup")
Reported-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220908130937.2795-1-jack@suse.cz
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This is useful for polled IO on a file, or for polled IO with the
io_uring passthrough mechanism. If bio allocations are done with
REQ_POLLED for those cases, then initializing the bio set with
BIOSET_PERCPU_CACHE enables the local per-cpu cache which eliminates
allocations (and frees) of bio structs when possible.
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There are two problems can lead to lost wakeup:
1) invalid wakeup on the wrong waitqueue:
For example, 2 * wake_batch tags are put, while only wake_batch threads
are woken:
__sbq_wake_up
atomic_cmpxchg -> reset wait_cnt
__sbq_wake_up -> decrease wait_cnt
...
__sbq_wake_up -> wait_cnt is decreased to 0 again
atomic_cmpxchg
sbq_index_atomic_inc -> increase wake_index
wake_up_nr -> wake up and waitqueue might be empty
sbq_index_atomic_inc -> increase again, one waitqueue is skipped
wake_up_nr -> invalid wake up because old wakequeue might be empty
To fix the problem, increasing 'wake_index' before resetting 'wait_cnt'.
2) 'wait_cnt' can be decreased while waitqueue is empty
As pointed out by Jan Kara, following race is possible:
CPU1 CPU2
__sbq_wake_up __sbq_wake_up
sbq_wake_ptr() sbq_wake_ptr() -> the same
wait_cnt = atomic_dec_return()
/* decreased to 0 */
sbq_index_atomic_inc()
/* move to next waitqueue */
atomic_set()
/* reset wait_cnt */
wake_up_nr()
/* wake up on the old waitqueue */
wait_cnt = atomic_dec_return()
/*
* decrease wait_cnt in the old
* waitqueue, while it can be
* empty.
*/
Fix the problem by waking up before updating 'wake_index' and
'wait_cnt'.
With this patch, noted that 'wait_cnt' is still decreased in the old
empty waitqueue, however, the wakeup is redirected to a active waitqueue,
and the extra decrement on the old empty waitqueue is not handled.
Fixes: 88459642cb ("blk-mq: abstract tag allocation out into sbitmap library")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220803121504.212071-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Avoid a kmalloc+kfree for each page array, if we only have a few pages
that are mapped. An alloc+free for each IO is quite expensive, and
it's pretty pointless if we're only dealing with 1 or a few vecs.
Use UIO_FASTIOV like we do in other spots to set a sane limit for how
big of an IO we want to avoid allocations for.
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
bdev based polled O_DIRECT is currently quite a bit faster than
passthru on the same device, and one of the reaons is that we're not
able to use the bio caching for passthru IO.
If REQ_POLLED is set on the request, use the fs bio set for grabbing a
bio from the caches, if available. This saves 5-6% of CPU over head
for polled passthru IO.
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We don't need full ints for several of these members. Change the
page_order and nr_entries to unsigned shorts, and the true/false from_user
and null_mapped to booleans.
This shrinks the struct from 32 to 24 bytes on 64-bit archs.
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add event tracing mechanism for following routines:
- create_sess()
- destroy_sess()
- process_rdma()
- process_msg_sess_info()
- process_msg_open()
- process_msg_close()
How to use:
1. Load the rnbd_server module
2. cd /sys/kernel/debug/tracing
3. If all the events need to be enabled:
echo 1 > events/rnbd_srv/enable
4. OR only speific routine/event needs to be enabled e.g.
echo 1 > events/rnbd_srv/create_sess/enable
5. cat trace
5. Run some workload which can trigger create_sess() routine/event
Signed-off-by: Santosh Pradhan <santosh.pradhan@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Link: https://lore.kernel.org/r/20220818105551.110490-2-haris.iqbal@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Provide a mechanism to retrieve basic status information about
the device, including the "supported" flag indicating whether
SED-OPAL is supported. The information returned is from the various
feature descriptors received during the discovery0 step, and so
this ioctl does nothing more than perform the discovery0 step
and then save the information received. See "struct opal_status"
and OPAL_FL_* bits for the status information currently returned.
This is necessary to be able to check whether a device is OPAL
enabled, set up, locked or unlocked from userspace programs
like systemd-cryptsetup and libcryptsetup. Right now we just
have to assume the user 'knows' or blindly attempt setup/lock/unlock
operations.
Signed-off-by: Douglas Miller <dougmill@linux.vnet.ibm.com>
Tested-by: Luca Boccassi <bluca@debian.org>
Reviewed-by: Scott Bauer <sbauer@plzdonthack.me>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Link: https://lore.kernel.org/r/20220816140713.84893-1-luca.boccassi@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull x86 kprobes fix from Ingo Molnar:
"Fix a kprobes bug in JNG/JNLE emulation when a kprobe is installed at
such instructions, possibly resulting in incorrect execution (the
wrong branch taken)"
* tag 'perf-urgent-2022-08-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/kprobes: Fix JNG/JNLE emulation
Pull tracing fixes from Steven Rostedt:
"Various fixes for tracing:
- Fix a return value of traceprobe_parse_event_name()
- Fix NULL pointer dereference from failed ftrace enabling
- Fix NULL pointer dereference when asking for registers from eprobes
- Make eprobes consistent with kprobes/uprobes, filters and
histograms"
* tag 'trace-v6.0-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Have filter accept "common_cpu" to be consistent
tracing/probes: Have kprobes and uprobes use $COMM too
tracing/eprobes: Have event probes be consistent with kprobes and uprobes
tracing/eprobes: Fix reading of string fields
tracing/eprobes: Do not hardcode $comm as a string
tracing/eprobes: Do not allow eprobes to use $stack, or % for regs
ftrace: Fix NULL pointer dereference in is_ftrace_trampoline when ftrace is dead
tracing/perf: Fix double put of trace event when init fails
tracing: React to error return from traceprobe_parse_event_name()
Currently, if a symbol "@" is attempted to be used with an event probe
(eprobes), it will cause a NULL pointer dereference crash.
Both kprobes and uprobes can reference data other than the main registers.
Such as immediate address, symbols and the current task name. Have eprobes
do the same thing.
For "comm", if "comm" is used and the event being attached to does not
have the "comm" field, then make it the "$comm" that kprobes has. This is
consistent to the way histograms and filters work.
Link: https://lkml.kernel.org/r/20220820134401.136924220@goodmis.org
Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Fixes: 7491e2c442 ("tracing: Add a probe that attaches to trace events")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
If in perf_trace_event_init(), the perf_trace_event_open() fails, then it
will call perf_trace_event_unreg() which will not only unregister the perf
trace event, but will also call the put() function of the tp_event.
The problem here is that the trace_event_try_get_ref() is called by the
caller of perf_trace_event_init() and if perf_trace_event_init() returns a
failure, it will then call trace_event_put(). But since the
perf_trace_event_unreg() already called the trace_event_put() function, it
triggers a WARN_ON().
WARNING: CPU: 1 PID: 30309 at kernel/trace/trace_dynevent.c:46 trace_event_dyn_put_ref+0x15/0x20
If perf_trace_event_reg() does not call the trace_event_try_get_ref() then
the perf_trace_event_unreg() should not be calling trace_event_put(). This
breaks symmetry and causes bugs like these.
Pull out the trace_event_put() from perf_trace_event_unreg() and call it
in the locations that perf_trace_event_unreg() is called. This not only
fixes this bug, but also brings back the proper symmetry of the reg/unreg
vs get/put logic.
Link: https://lore.kernel.org/all/cover.1660347763.git.kjlx@templeofstupid.com/
Link: https://lkml.kernel.org/r/20220816192817.43d5e17f@gandalf.local.home
Cc: stable@vger.kernel.org
Fixes: 1d18538e6a ("tracing: Have dynamic events have a ref counter")
Reported-by: Krister Johansen <kjlx@templeofstupid.com>
Reviewed-by: Krister Johansen <kjlx@templeofstupid.com>
Tested-by: Krister Johansen <kjlx@templeofstupid.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The function traceprobe_parse_event_name() may set the first two function
arguments to a non-null value and still return -EINVAL to indicate an
unsuccessful completion of the function. Hence, it is not sufficient to
just check the result of the two function arguments for being not null,
but the return value also needs to be checked.
Commit 95c104c378 ("tracing: Auto generate event name when creating a
group of events") changed the error-return-value checking of the second
traceprobe_parse_event_name() invocation in __trace_eprobe_create() and
removed checking the return value to jump to the error handling case.
Reinstate using the return value in the error-return-value checking.
Link: https://lkml.kernel.org/r/20220811071734.20700-1-lukas.bulwahn@gmail.com
Fixes: 95c104c378 ("tracing: Auto generate event name when creating a group of events")
Acked-by: Linyu Yuan <quic_linyyuan@quicinc.com>
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Pull i2c fixes from Wolfram Sang:
"A revert to fix a regression introduced this merge window and a fix
for proper error handling in the remove path of the iMX driver"
* tag 'i2c-for-6.0-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
i2c: imx: Make sure to unregister adapter on remove()
Revert "i2c: scmi: Replace open coded device_get_match_data()"
Pull cifs client fixes from Steve French:
- memory leak fix
- two small cleanups
- trivial strlcpy removal
- update missing entry for cifs headers in MAINTAINERS file
* tag '6.0-rc1-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
cifs: move from strlcpy with unused retval to strscpy
cifs: Fix memory leak on the deferred close
cifs: remove useless parameter 'is_fsctl' from SMB2_ioctl()
cifs: remove unused server parameter from calc_smb_size()
cifs: missing directory in MAINTAINERS file
If for whatever reasons pm_runtime_resume_and_get() fails and .remove() is
exited early, the i2c adapter stays around and the irq still calls its
handler, while the driver data and the register mapping go away. So if
later the i2c adapter is accessed or the irq triggers this results in
havoc accessing freed memory and unmapped registers.
So unregister the software resources even if resume failed, and only skip
the hardware access in that case.
Fixes: 588eb93ea4 ("i2c: imx: add runtime pm support to improve the performance")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Pull Kbuild fixes from Masahiro Yamada:
- Fix module versioning broken on some architectures
- Make dummy-tools enable CONFIG_PPC_LONG_DOUBLE_128
- Remove -Wformat-zero-length, which has no warning instance
- Fix the order between drivers and libs in modules.order
- Fix false-positive warnings in clang-analyzer
* tag 'kbuild-fixes-v6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
scripts/clang-tools: Remove DeprecatedOrUnsafeBufferHandling check
kbuild: fix the modules order between drivers and libs
scripts/Makefile.extrawarn: Do not disable clang's -Wformat-zero-length
kbuild: dummy-tools: pretend we understand __LONG_DOUBLE_128__
modpost: fix module versioning when a symbol lacks valid CRC
Pull perf tools fixes from Arnaldo Carvalho de Melo:
- Fix alignment for cpu map masks in event encoding.
- Support reading PERF_FORMAT_LOST, perf tool counterpart for a feature
that was added in this merge window.
- Sync perf tools copies of kernel headers: socket, msr-index, fscrypt,
cpufeatures, i915_drm, kvm, vhost, perf_event.
* tag 'perf-tools-fixes-for-v6.0-2022-08-19' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux:
perf tools: Support reading PERF_FORMAT_LOST
libperf: Add a test case for read formats
libperf: Handle read format in perf_evsel__read()
tools headers UAPI: Sync linux/perf_event.h with the kernel sources
tools headers UAPI: Sync x86's asm/kvm.h with the kernel sources
tools headers UAPI: Sync KVM's vmx.h header with the kernel sources
tools include UAPI: Sync linux/vhost.h with the kernel sources
tools headers kvm s390: Sync headers with the kernel sources
tools headers UAPI: Sync linux/kvm.h with the kernel sources
tools headers UAPI: Sync drm/i915_drm.h with the kernel sources
tools headers cpufeatures: Sync with the kernel sources
tools headers UAPI: Sync linux/fscrypt.h with the kernel sources
tools arch x86: Sync the msr-index.h copy with the kernel sources
perf beauty: Update copy of linux/socket.h with the kernel sources
perf cpumap: Fix alignment for masks in event encoding
perf cpumap: Compute mask size in constant time
perf cpumap: Synthetic events and const/static
perf cpumap: Const map for max()
Pull s390 updates from Alexander Gordeev:
- Fix a KVM crash on z12 and older machines caused by a wrong
assumption that Query AP Configuration Information is always
available.
- Lower severity of excessive Hypervisor filesystem error messages
when booting under KVM.
* tag 's390-6.0-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/ap: fix crash on older machines based on QCI info missing
s390/hypfs: avoid error message under KVM
