Igor Raits and Bagas Sanjaya report a RQCF_ACT_SKIP leak warning.
Link: https://lore.kernel.org/all/a5dd536d-041a-2ce9-f4b7-64d8d85c86dc@gmail.com
This warning may be triggered in the following situations:
CPU0 CPU1
__schedule()
*rq->clock_update_flags <<= 1;* unregister_fair_sched_group()
pick_next_task_fair+0x4a/0x410 destroy_cfs_bandwidth()
newidle_balance+0x115/0x3e0 for_each_possible_cpu(i) *i=0*
rq_unpin_lock(this_rq, rf) __cfsb_csd_unthrottle()
raw_spin_rq_unlock(this_rq)
rq_lock(*CPU0_rq*, &rf)
rq_clock_start_loop_update()
rq->clock_update_flags & RQCF_ACT_SKIP <--
raw_spin_rq_lock(this_rq)
The purpose of RQCF_ACT_SKIP is to skip the update rq clock,
but the update is very early in __schedule(), but we clear
RQCF_*_SKIP very late, causing it to span that gap above
and triggering this warning.
In __schedule() we can clear the RQCF_*_SKIP flag immediately
after update_rq_clock() to avoid this RQCF_ACT_SKIP leak warning.
And set rq->clock_update_flags to RQCF_UPDATED to avoid
rq->clock_update_flags < RQCF_ACT_SKIP warning that may be triggered later.
Fixes: ebb83d84e49b ("sched/core: Avoid multiple calling update_rq_clock() in __cfsb_csd_unthrottle()")
Cc: stable(a)vger.kernel.org
Reported-by: Igor Raits <igor.raits(a)gmail.com>
Reported-by: Bagas Sanjaya <bagasdotme(a)gmail.com>
Closes: https://lore.kernel.org/all/20230913082424.73252-1-jiahao.os@bytedance.com
Suggested-by: Peter Zijlstra (Intel) <peterz(a)infradead.org>
Signed-off-by: Hao Jia <jiahao.os(a)bytedance.com>
---
kernel/sched/core.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 802551e0009b..afb8d213155b 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5374,8 +5374,6 @@ context_switch(struct rq *rq, struct task_struct *prev,
/* switch_mm_cid() requires the memory barriers above. */
switch_mm_cid(rq, prev, next);
- rq->clock_update_flags &= ~(RQCF_ACT_SKIP|RQCF_REQ_SKIP);
-
prepare_lock_switch(rq, next, rf);
/* Here we just switch the register state and the stack. */
@@ -6615,6 +6613,7 @@ static void __sched notrace __schedule(unsigned int sched_mode)
/* Promote REQ to ACT */
rq->clock_update_flags <<= 1;
update_rq_clock(rq);
+ rq->clock_update_flags = RQCF_UPDATED;
switch_count = &prev->nivcsw;
@@ -6694,8 +6693,6 @@ static void __sched notrace __schedule(unsigned int sched_mode)
/* Also unlocks the rq: */
rq = context_switch(rq, prev, next, &rf);
} else {
- rq->clock_update_flags &= ~(RQCF_ACT_SKIP|RQCF_REQ_SKIP);
-
rq_unpin_lock(rq, &rf);
__balance_callbacks(rq);
raw_spin_rq_unlock_irq(rq);
--
2.39.2
If name_show() is non unique, this test will try to install a kprobe on this
function which should fail returning EADDRNOTAVAIL.
On kernel where name_show() is not unique, this test is skipped.
Cc: stable(a)vger.kernel.org
Signed-off-by: Francis Laniel <flaniel(a)linux.microsoft.com>
---
.../ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc | 13 +++++++++++++
1 file changed, 13 insertions(+)
create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc
diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc
new file mode 100644
index 000000000000..bc9514428dba
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc
@@ -0,0 +1,13 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Test failure of registering kprobe on non unique symbol
+# requires: kprobe_events
+
+SYMBOL='name_show'
+
+# We skip this test on kernel where SYMBOL is unique or does not exist.
+if [ "$(grep -c -E "[[:alnum:]]+ t ${SYMBOL}" /proc/kallsyms)" -le '1' ]; then
+ exit_unsupported
+fi
+
+! echo "p:test_non_unique ${SYMBOL}" > kprobe_events
--
2.34.1
When a kprobe is attached to a function that's name is not unique (is
static and shares the name with other functions in the kernel), the
kprobe is attached to the first function it finds. This is a bug as the
function that it is attaching to is not necessarily the one that the
user wants to attach to.
Instead of blindly picking a function to attach to what is ambiguous,
error with EADDRNOTAVAIL to let the user know that this function is not
unique, and that the user must use another unique function with an
address offset to get to the function they want to attach to.
Cc: stable(a)vger.kernel.org
Fixes: 413d37d1eb69 ("tracing: Add kprobe-based event tracer")
Suggested-by: Masami Hiramatsu <mhiramat(a)kernel.org>
Signed-off-by: Francis Laniel <flaniel(a)linux.microsoft.com>
Link: https://lore.kernel.org/lkml/20230819101105.b0c104ae4494a7d1f2eea742@kernel…
---
kernel/trace/trace_kprobe.c | 63 +++++++++++++++++++++++++++++++++++++
kernel/trace/trace_probe.h | 1 +
2 files changed, 64 insertions(+)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 3d7a180a8427..a8fef6ab0872 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -705,6 +705,25 @@ static struct notifier_block trace_kprobe_module_nb = {
.priority = 1 /* Invoked after kprobe module callback */
};
+static int count_symbols(void *data, unsigned long unused)
+{
+ unsigned int *count = data;
+
+ (*count)++;
+
+ return 0;
+}
+
+static unsigned int number_of_same_symbols(char *func_name)
+{
+ unsigned int count;
+
+ count = 0;
+ kallsyms_on_each_match_symbol(count_symbols, func_name, &count);
+
+ return count;
+}
+
static int __trace_kprobe_create(int argc, const char *argv[])
{
/*
@@ -836,6 +855,31 @@ static int __trace_kprobe_create(int argc, const char *argv[])
}
}
+ if (symbol && !strchr(symbol, ':')) {
+ unsigned int count;
+
+ count = number_of_same_symbols(symbol);
+ if (count > 1) {
+ /*
+ * Users should use ADDR to remove the ambiguity of
+ * using KSYM only.
+ */
+ trace_probe_log_err(0, NON_UNIQ_SYMBOL);
+ ret = -EADDRNOTAVAIL;
+
+ goto error;
+ } else if (count == 0) {
+ /*
+ * We can return ENOENT earlier than when register the
+ * kprobe.
+ */
+ trace_probe_log_err(0, BAD_PROBE_ADDR);
+ ret = -ENOENT;
+
+ goto error;
+ }
+ }
+
trace_probe_log_set_index(0);
if (event) {
ret = traceprobe_parse_event_name(&event, &group, gbuf,
@@ -1695,6 +1739,7 @@ static int unregister_kprobe_event(struct trace_kprobe *tk)
}
#ifdef CONFIG_PERF_EVENTS
+
/* create a trace_kprobe, but don't add it to global lists */
struct trace_event_call *
create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
@@ -1705,6 +1750,24 @@ create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
int ret;
char *event;
+ if (func) {
+ unsigned int count;
+
+ count = number_of_same_symbols(func);
+ if (count > 1)
+ /*
+ * Users should use addr to remove the ambiguity of
+ * using func only.
+ */
+ return ERR_PTR(-EADDRNOTAVAIL);
+ else if (count == 0)
+ /*
+ * We can return ENOENT earlier than when register the
+ * kprobe.
+ */
+ return ERR_PTR(-ENOENT);
+ }
+
/*
* local trace_kprobes are not added to dyn_event, so they are never
* searched in find_trace_kprobe(). Therefore, there is no concern of
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 02b432ae7513..850d9ecb6765 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -450,6 +450,7 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call,
C(BAD_MAXACT, "Invalid maxactive number"), \
C(MAXACT_TOO_BIG, "Maxactive is too big"), \
C(BAD_PROBE_ADDR, "Invalid probed address or symbol"), \
+ C(NON_UNIQ_SYMBOL, "The symbol is not unique"), \
C(BAD_RETPROBE, "Retprobe address must be an function entry"), \
C(NO_TRACEPOINT, "Tracepoint is not found"), \
C(BAD_ADDR_SUFFIX, "Invalid probed address suffix"), \
--
2.34.1
Hi.
In the kernel source code, it exists different functions which share the same
name but which have, of course, different addresses as they can be defined in
different modules:
# Kernel was compiled with CONFIG_NTFS_FS and CONFIG_NTFS3_FS as built-in.
root@vm-amd64:~# grep ntfs_file_write_iter /proc/kallsyms
ffffffff814ce3c0 t __pfx_ntfs_file_write_iter
ffffffff814ce3d0 t ntfs_file_write_iter
ffffffff814fc8a0 t __pfx_ntfs_file_write_iter
ffffffff814fc8b0 t ntfs_file_write_iter
This can be source of troubles when you create a PMU kprobe for such a function,
as it will only install one for the first address (e.g. 0xffffffff814ce3d0 in
the above).
This could lead to some troubles were BPF based tools does not report any event
because the second function is not called:
root@vm-amd64:/mnt# mount | grep /mnt
/foo.img on /mnt type ntfs3 (rw,relatime,uid=0,gid=0,iocharset=utf8)
# ig is a tool which installs a PMU kprobe on ntfs_file_write_iter().
root@vm-amd64:/mnt# ig trace fsslower -m 0 -f ntfs3 --host &> /tmp/foo &
[1] 207
root@vm-amd64:/mnt# dd if=./foo of=./bar count=3
3+0 records in
3+0 records out
1536 bytes (1.5 kB, 1.5 KiB) copied, 0.00543323 s, 283 kB/s
root@vm-amd64:/mnt# fg
ig trace fsslower -m 0 -f ntfs3 --host &> /tmp/foo
^Croot@vm-amd64:/mnt# more /tmp/foo
RUNTIME.CONTAINERNAME RUNTIME.CONTAIN… PID COMM
T BYTES OFFSET LAT FILE
214 dd
R 512 0 766 foo
214 dd
R 512 512 9 foo
214 dd
As you can see in the above, only read events are reported and no write because
the kprobe is installed for the old ntfs_file_write_iter() and not the ntfs3
one.
The same behavior occurs with sysfs kprobe:
root@vm-amd64:/# echo 'p:probe/ntfs_file_write_iter ntfs_file_write_iter' > /sys/kernel/tracing/kprobe_events
root@vm-amd64:/# cat /sys/kernel/tracing/kprobe_events
p:probe/ntfs_file_write_iter ntfs_file_write_iter
root@vm-amd64:/# mount | grep /mnt
/foo.img on /mnt type ntfs3 (rw,relatime,uid=0,gid=0,iocharset=utf8)
root@vm-amd64:/# perf record -e probe:ntfs_file_write_iter &
[1] 210
root@vm-amd64:/# cd /mnt/
root@vm-amd64:/mnt# dd if=./foo of=./bar count=3
3+0 records in
3+0 records out
1536 bytes (1.5 kB, 1.5 KiB) copied, 0.00234793 s, 654 kB/s
root@vm-amd64:/mnt# cd -
/
root@vm-amd64:/# fg
perf record -e probe:ntfs_file_write_iter
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.056 MB perf.data ]
root@vm-amd64:/# perf report
Error:
The perf.data data has no samples!
# To display the perf.data header info, please use --header/--header-only optio>
#
In this contribution, I modified the functions creating sysfs and PMU kprobes to
test if the function name given as argument matches several symbols.
In this case, these functions return EADDRNOTAVAIL to indicate the user to use
addr and offs to remove this ambiguity.
So, when the above BPF tool is run, the following error message is printed:
root@vm-amd64:~# ig trace fsslower -m 0 -f ntfs3 --host &> /tmp/foo &
[1] 228
root@vm-amd64:~# more /tmp/foo
RUNTIME.CONTAINERNAME RUNTIME.CONTAIN… PID COMM
T BYTES OFFSET LAT FILE
Error: running gadget: running gadget: installing tracer: attaching kprobe: crea
ting perf_kprobe PMU (arch-specific fallback for "ntfs_file_write_iter"): token
ntfs_file_write_iter: opening perf event: cannot assign requested address
And the same with sysfs kprobe:
root@vm-amd64:/# echo 'p:probe/ntfs_file_write_iter ntfs_file_write_iter' > /sys/kernel/tracing/kprobe_events
-bash: echo: write error: Cannot assign requested address
Note that, this does not influence perf as it installs kprobes as offset on
_text:
root@vm-amd64:/# perf probe --add ntfs_file_write_iter
Added new events:
probe:ntfs_file_write_iter (on ntfs_file_write_iter)
probe:ntfs_file_write_iter (on ntfs_file_write_iter)
...
root@vm-amd64:/# cat /sys/kernel/tracing/kprobe_events
p:probe/ntfs_file_write_iter _text+5039088
p:probe/ntfs_file_write_iter _text+5228752
Note that, this contribution is the conclusion of a previous RFC which intended
to install a PMU kprobe for all matching symbols [1, 2].
If you see any way to improve this contribution, particularly if you have an
idea to add tests or documentation for this behavior, please share your
feedback.
Changes since:
v1:
* Use EADDRNOTAVAIL instead of adding a new error code.
* Correct also this behavior for sysfs kprobe.
v2:
* Count the number of symbols corresponding to function name and return
EADDRNOTAVAIL if higher than 1.
* Return ENOENT if above count is 0, as it would be returned later by while
registering the kprobe.
v3:
* Check symbol does not contain ':' before testing its uniqueness.
* Add a selftest to check this is not possible to install a kprobe for a non
unique symbol.
v5:
* No changes, just add linux-stable as recipient.
Francis Laniel (2):
tracing/kprobes: Return EADDRNOTAVAIL when func matches several
symbols
selftests/ftrace: Add new test case which checks non unique symbol
kernel/trace/trace_kprobe.c | 63 +++++++++++++++++++
kernel/trace/trace_probe.h | 1 +
.../test.d/kprobe/kprobe_non_uniq_symbol.tc | 13 ++++
3 files changed, 77 insertions(+)
create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc
Best regards and thank you in advance.
---
[1]: https://lore.kernel.org/lkml/20230816163517.112518-1-flaniel@linux.microsof…
[2]: https://lore.kernel.org/lkml/20230819101105.b0c104ae4494a7d1f2eea742@kernel…
--
2.34.1
On Sun, Sep 03, 2023 at 09:19:13PM +0900, Kenta Sato wrote:
> Hi,
>
> I am using the FriendlyElec NanoPi R4S board.
> When I update the kernel from 6.4.7 to 6.4.11, 6.4.13, and 6.5.1, it
> doesn't recognize some USB devices.
>
> The board has two USB 3.0 ports. I connected 1) BUFFALO USB Flash Disk
> (high-speed) and 2) NETGEAR A6210 (SuperSpeed) to each port.
> 1) is often not recognized. On the other hand, 2) was working while I
> was testing.
> Regardless of whether a USB device is connected, I could see the below
> message on dmesg:
>
> [ 0.740993] phy phy-ff7c0000.phy.8: phy poweron failed --> -110
> [ 0.741585] dwc3 fe800000.usb: error -ETIMEDOUT: failed to initialize core
> [ 0.742334] dwc3: probe of fe800000.usb failed with error -110
> [ 0.751635] rockchip-usb2phy ff770000.syscon:usb2phy@e460:
> Requested PHY is disabled
>
> Is there any idea on this?
>
> The cause seems to be related to this commit. I tried reverting this
> change and the issue seemed to be solved.
>
> >From 317d6e4c12b46bde61248ea4ab5e19f68cbd1c57 Mon Sep 17 00:00:00 2001
> From: Jisheng Zhang <jszhang(a)kernel.org>
> Date: Wed, 28 Jun 2023 00:20:18 +0800
> Subject: usb: dwc3: don't reset device side if dwc3 was configured as
> host-only
>
> commit e835c0a4e23c38531dcee5ef77e8d1cf462658c7 upstream.
>
> Commit c4a5153e87fd ("usb: dwc3: core: Power-off core/PHYs on
> system_suspend in host mode") replaces check for HOST only dr_mode with
> current_dr_role. But during booting, the current_dr_role isn't
> initialized, thus the device side reset is always issued even if dwc3
> was configured as host-only. What's more, on some platforms with host
> only dwc3, aways issuing device side reset by accessing device register
> block can cause kernel panic.
>
> Fixes: c4a5153e87fd ("usb: dwc3: core: Power-off core/PHYs on
> system_suspend in host mode")
> Cc: stable <stable(a)kernel.org>
> Signed-off-by: Jisheng Zhang <jszhang(a)kernel.org>
> Acked-by: Thinh Nguyen <Thinh.Nguyen(a)synopsys.com>
> Link: https://lore.kernel.org/r/20230627162018.739-1-jszhang@kernel.org
> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
> ---
> drivers/usb/dwc3/core.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=…
>
Thanks for the regression report. I'm adding it to regzbot:
#regzbot ^introduced: e835c0a4e23c38
#regzbot title: some USB devices unrecognized caused by not resetting dwc3 device if it is host-only
--
An old man doll... just what I always wanted! - Clara
With every release of LLVM, both of these sanitizers eat up more and
more of the stack. So, set FRAME_WARN to 0 if either of them is enabled
for a given build.
Cc: stable(a)vger.kernel.org
Signed-off-by: Hamza Mahfooz <hamza.mahfooz(a)amd.com>
---
lib/Kconfig.debug | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 39d1d93164bd..15ad742729ca 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -429,11 +429,10 @@ endif # DEBUG_INFO
config FRAME_WARN
int "Warn for stack frames larger than"
range 0 8192
- default 0 if KMSAN
+ default 0 if KASAN || KCSAN || KMSAN
default 2048 if GCC_PLUGIN_LATENT_ENTROPY
default 2048 if PARISC
default 1536 if (!64BIT && XTENSA)
- default 1280 if KASAN && !64BIT
default 1024 if !64BIT
default 2048 if 64BIT
help
--
2.42.0