This patch series is inspired by the cpuset patch sent by Sun Shaojie [1].
The idea is to avoid invalidating sibling partitions when there is a
cpuset.cpus conflict. However this patch series does it in a slightly
different way to make its behavior more consistent with other cpuset
properties.
The first 3 patches are just some cleanup and minor bug fixes on
issues found during the investigation process. The last one is
the major patch that changes the way cpuset.cpus is being handled
during the partition creation process. Instead of invalidating sibling
partitions when there is a conflict, it will strip out the conflicting
exclusive CPUs and assign the remaining non-conflicting exclusive
CPUs to the new partition unless there is no more CPU left which will
fail the partition creation process. It is similar to the idea that
cpuset.cpus.effective may only contain a subset of CPUs specified in
cpuset.cpus. So cpuset.cpus.exclusive.effective may contain only a
subset of cpuset.cpus when a partition is created without setting
cpuset.cpus.exclusive.
Even setting cpuset.cpus.exclusive instead of cpuset.cpus may not
guarantee all the requested CPUs can be granted if parent doesn't have
access to some of those exclusive CPUs. The difference is that conflicts
from siblings is not possible with cpuset.cpus.exclusive as long as it
can be set successfully without failure.
[1] https://lore.kernel.org/lkml/20251117015708.977585-1-sunshaojie@kylinos.cn/
Waiman Long (4):
cgroup/cpuset: Streamline rm_siblings_excl_cpus()
cgroup/cpuset: Consistently compute effective_xcpus in
update_cpumasks_hier()
cgroup/cpuset: Don't fail cpuset.cpus change in v2
cgroup/cpuset: Don't invalidate sibling partitions on cpuset.cpus
conflict
kernel/cgroup/cpuset-internal.h | 3 +
kernel/cgroup/cpuset-v1.c | 19 +++
kernel/cgroup/cpuset.c | 135 +++++++-----------
.../selftests/cgroup/test_cpuset_prs.sh | 26 +++-
4 files changed, 93 insertions(+), 90 deletions(-)
--
2.52.0
The SBI Firmware Feature extension allows the S-mode to request some
specific features (either hardware or software) to be enabled. This
series uses this extension to request misaligned access exception
delegation to S-mode in order to let the kernel handle it. It also adds
support for the KVM FWFT SBI extension based on the misaligned access
handling infrastructure.
FWFT SBI extension is part of the SBI V3.0 specifications [1]. It can be
tested using the qemu provided at [2] which contains the series from
[3]. Upstream kvm-unit-tests can be used inside kvm to tests the correct
delegation of misaligned exceptions. Upstream OpenSBI can be used.
Note: Since SBI V3.0 is not yet ratified, FWFT extension API is split
between interface only and implementation, allowing to pick only the
interface which do not have hard dependencies on SBI.
The tests can be run using the kselftest from series [4].
$ qemu-system-riscv64 \
-cpu rv64,trap-misaligned-access=true,v=true \
-M virt \
-m 1024M \
-bios fw_dynamic.bin \
-kernel Image
...
# ./misaligned
TAP version 13
1..23
# Starting 23 tests from 1 test cases.
# RUN global.gp_load_lh ...
# OK global.gp_load_lh
ok 1 global.gp_load_lh
# RUN global.gp_load_lhu ...
# OK global.gp_load_lhu
ok 2 global.gp_load_lhu
# RUN global.gp_load_lw ...
# OK global.gp_load_lw
ok 3 global.gp_load_lw
# RUN global.gp_load_lwu ...
# OK global.gp_load_lwu
ok 4 global.gp_load_lwu
# RUN global.gp_load_ld ...
# OK global.gp_load_ld
ok 5 global.gp_load_ld
# RUN global.gp_load_c_lw ...
# OK global.gp_load_c_lw
ok 6 global.gp_load_c_lw
# RUN global.gp_load_c_ld ...
# OK global.gp_load_c_ld
ok 7 global.gp_load_c_ld
# RUN global.gp_load_c_ldsp ...
# OK global.gp_load_c_ldsp
ok 8 global.gp_load_c_ldsp
# RUN global.gp_load_sh ...
# OK global.gp_load_sh
ok 9 global.gp_load_sh
# RUN global.gp_load_sw ...
# OK global.gp_load_sw
ok 10 global.gp_load_sw
# RUN global.gp_load_sd ...
# OK global.gp_load_sd
ok 11 global.gp_load_sd
# RUN global.gp_load_c_sw ...
# OK global.gp_load_c_sw
ok 12 global.gp_load_c_sw
# RUN global.gp_load_c_sd ...
# OK global.gp_load_c_sd
ok 13 global.gp_load_c_sd
# RUN global.gp_load_c_sdsp ...
# OK global.gp_load_c_sdsp
ok 14 global.gp_load_c_sdsp
# RUN global.fpu_load_flw ...
# OK global.fpu_load_flw
ok 15 global.fpu_load_flw
# RUN global.fpu_load_fld ...
# OK global.fpu_load_fld
ok 16 global.fpu_load_fld
# RUN global.fpu_load_c_fld ...
# OK global.fpu_load_c_fld
ok 17 global.fpu_load_c_fld
# RUN global.fpu_load_c_fldsp ...
# OK global.fpu_load_c_fldsp
ok 18 global.fpu_load_c_fldsp
# RUN global.fpu_store_fsw ...
# OK global.fpu_store_fsw
ok 19 global.fpu_store_fsw
# RUN global.fpu_store_fsd ...
# OK global.fpu_store_fsd
ok 20 global.fpu_store_fsd
# RUN global.fpu_store_c_fsd ...
# OK global.fpu_store_c_fsd
ok 21 global.fpu_store_c_fsd
# RUN global.fpu_store_c_fsdsp ...
# OK global.fpu_store_c_fsdsp
ok 22 global.fpu_store_c_fsdsp
# RUN global.gen_sigbus ...
[12797.988647] misaligned[618]: unhandled signal 7 code 0x1 at 0x0000000000014dc0 in misaligned[4dc0,10000+76000]
[12797.988990] CPU: 0 UID: 0 PID: 618 Comm: misaligned Not tainted 6.13.0-rc6-00008-g4ec4468967c9-dirty #51
[12797.989169] Hardware name: riscv-virtio,qemu (DT)
[12797.989264] epc : 0000000000014dc0 ra : 0000000000014d00 sp : 00007fffe165d100
[12797.989407] gp : 000000000008f6e8 tp : 0000000000095760 t0 : 0000000000000008
[12797.989544] t1 : 00000000000965d8 t2 : 000000000008e830 s0 : 00007fffe165d160
[12797.989692] s1 : 000000000000001a a0 : 0000000000000000 a1 : 0000000000000002
[12797.989831] a2 : 0000000000000000 a3 : 0000000000000000 a4 : ffffffffdeadbeef
[12797.989964] a5 : 000000000008ef61 a6 : 626769735f6e0000 a7 : fffffffffffff000
[12797.990094] s2 : 0000000000000001 s3 : 00007fffe165d838 s4 : 00007fffe165d848
[12797.990238] s5 : 000000000000001a s6 : 0000000000010442 s7 : 0000000000010200
[12797.990391] s8 : 000000000000003a s9 : 0000000000094508 s10: 0000000000000000
[12797.990526] s11: 0000555567460668 t3 : 00007fffe165d070 t4 : 00000000000965d0
[12797.990656] t5 : fefefefefefefeff t6 : 0000000000000073
[12797.990756] status: 0000000200004020 badaddr: 000000000008ef61 cause: 0000000000000006
[12797.990911] Code: 8793 8791 3423 fcf4 3783 fc84 c737 dead 0713 eef7 (c398) 0001
# OK global.gen_sigbus
ok 23 global.gen_sigbus
# PASSED: 23 / 23 tests passed.
# Totals: pass:23 fail:0 xfail:0 xpass:0 skip:0 error:0
With kvm-tools:
# lkvm run -k sbi.flat -m 128
Info: # lkvm run -k sbi.flat -m 128 -c 1 --name guest-97
Info: Removed ghost socket file "/root/.lkvm//guest-97.sock".
##########################################################################
# kvm-unit-tests
##########################################################################
... [test messages elided]
PASS: sbi: fwft: FWFT extension probing no error
PASS: sbi: fwft: get/set reserved feature 0x6 error == SBI_ERR_DENIED
PASS: sbi: fwft: get/set reserved feature 0x3fffffff error == SBI_ERR_DENIED
PASS: sbi: fwft: get/set reserved feature 0x80000000 error == SBI_ERR_DENIED
PASS: sbi: fwft: get/set reserved feature 0xbfffffff error == SBI_ERR_DENIED
PASS: sbi: fwft: misaligned_deleg: Get misaligned deleg feature no error
PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature invalid value error
PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature invalid value error
PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature value no error
PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature value 0
PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature value no error
PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature value 1
PASS: sbi: fwft: misaligned_deleg: Verify misaligned load exception trap in supervisor
SUMMARY: 50 tests, 2 unexpected failures, 12 skipped
This series is available at [5].
Link: https://github.com/riscv-non-isa/riscv-sbi-doc/releases/download/vv3.0-rc2/… [1]
Link: https://github.com/rivosinc/qemu/tree/dev/cleger/misaligned [2]
Link: https://lore.kernel.org/all/20241211211933.198792-3-fkonrad@amd.com/T/ [3]
Link: https://lore.kernel.org/linux-riscv/20250414123543.1615478-1-cleger@rivosin… [4]
Link: https://github.com/rivosinc/linux/tree/dev/cleger/fwft [5]
---
V8:
- Move misaligned_access_speed under CONFIG_RISCV_MISALIGNED and add a
separate commit for that.
V7:
- Fix ifdefery build problems
- Move sbi_fwft_is_supported with fwft_set_req struct
- Added Atish Reviewed-by
- Updated KVM vcpu cfg hedeleg value in set_delegation
- Changed SBI ETIME error mapping to ETIMEDOUT
- Fixed a few typo reported by Alok
V6:
- Rename FWFT interface to remove "_local"
- Fix test for MEDELEG values in KVM FWFT support
- Add __init for unaligned_access_init()
- Rebased on master
V5:
- Return ERANGE as mapping for SBI_ERR_BAD_RANGE
- Removed unused sbi_fwft_get()
- Fix kernel for sbi_fwft_local_set_cpumask()
- Fix indentation for sbi_fwft_local_set()
- Remove spurious space in kvm_sbi_fwft_ops.
- Rebased on origin/master
- Remove fixes commits and sent them as a separate series [4]
V4:
- Check SBI version 3.0 instead of 2.0 for FWFT presence
- Use long for kvm_sbi_fwft operation return value
- Init KVM sbi extension even if default_disabled
- Remove revert_on_fail parameter for sbi_fwft_feature_set().
- Fix comments for sbi_fwft_set/get()
- Only handle local features (there are no globals yet in the spec)
- Add new SBI errors to sbi_err_map_linux_errno()
V3:
- Added comment about kvm sbi fwft supported/set/get callback
requirements
- Move struct kvm_sbi_fwft_feature in kvm_sbi_fwft.c
- Add a FWFT interface
V2:
- Added Kselftest for misaligned testing
- Added get_user() usage instead of __get_user()
- Reenable interrupt when possible in misaligned access handling
- Document that riscv supports unaligned-traps
- Fix KVM extension state when an init function is present
- Rework SBI misaligned accesses trap delegation code
- Added support for CPU hotplugging
- Added KVM SBI reset callback
- Added reset for KVM SBI FWFT lock
- Return SBI_ERR_DENIED_LOCKED when LOCK flag is set
Clément Léger (14):
riscv: sbi: add Firmware Feature (FWFT) SBI extensions definitions
riscv: sbi: remove useless parenthesis
riscv: sbi: add new SBI error mappings
riscv: sbi: add FWFT extension interface
riscv: sbi: add SBI FWFT extension calls
riscv: misaligned: request misaligned exception from SBI
riscv: misaligned: use on_each_cpu() for scalar misaligned access
probing
riscv: misaligned: declare misaligned_access_speed under
CONFIG_RISCV_MISALIGNED
riscv: misaligned: move emulated access uniformity check in a function
riscv: misaligned: add a function to check misalign trap delegability
RISC-V: KVM: add SBI extension init()/deinit() functions
RISC-V: KVM: add SBI extension reset callback
RISC-V: KVM: add support for FWFT SBI extension
RISC-V: KVM: add support for SBI_FWFT_MISALIGNED_DELEG
arch/riscv/include/asm/cpufeature.h | 14 +-
arch/riscv/include/asm/kvm_host.h | 5 +-
arch/riscv/include/asm/kvm_vcpu_sbi.h | 12 +
arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h | 29 +++
arch/riscv/include/asm/sbi.h | 60 +++++
arch/riscv/include/uapi/asm/kvm.h | 1 +
arch/riscv/kernel/sbi.c | 81 ++++++-
arch/riscv/kernel/traps_misaligned.c | 112 ++++++++-
arch/riscv/kernel/unaligned_access_speed.c | 8 +-
arch/riscv/kvm/Makefile | 1 +
arch/riscv/kvm/vcpu.c | 4 +-
arch/riscv/kvm/vcpu_sbi.c | 54 +++++
arch/riscv/kvm/vcpu_sbi_fwft.c | 257 +++++++++++++++++++++
arch/riscv/kvm/vcpu_sbi_sta.c | 3 +-
14 files changed, 620 insertions(+), 21 deletions(-)
create mode 100644 arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h
create mode 100644 arch/riscv/kvm/vcpu_sbi_fwft.c
--
2.49.0
When /sys/kernel/tracing/buffer_size_kb is less than 12KB,
the test_multiple_writes test will stall and wait for more
input due to insufficient buffer space.
This patch check current buffer_size_kb value before the test.
If it is less than 12KB, it temporarily increase the buffer to
12KB, and restore the original value after the tests are completed.
Fixes: 37f46601383a ("selftests/tracing: Add basic test for trace_marker_raw file")
Signed-off-by: Fushuai Wang <wangfushuai(a)baidu.com>
---
.../ftrace/test.d/00basic/trace_marker_raw.tc | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc b/tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc
index 7daf7292209e..216f87d89c3f 100644
--- a/tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc
+++ b/tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc
@@ -58,7 +58,7 @@ test_multiple_writes() {
echo stop > trace_marker
# Check to make sure the number of entries is the id (rounded up by 4)
- awk '/.*: # [0-9a-f]* / {
+ awk -v ORIG="${ORIG}" '/.*: # [0-9a-f]* / {
print;
cnt = -1;
for (i = 0; i < NF; i++) {
@@ -70,6 +70,7 @@ test_multiple_writes() {
# The number of items is always rounded up by 4
cnt2 = int((cnt + 3) / 4) * 4;
if (cnt2 != num) {
+ system("echo \""ORIG"\" > buffer_size_kb");
exit 1;
}
break;
@@ -89,6 +90,7 @@ test_buffer() {
# The id must be four bytes, test that 3 bytes fails a write
if echo -n abc > ./trace_marker_raw ; then
echo "Too small of write expected to fail but did not"
+ echo $ORIG > buffer_size_kb
exit_fail
fi
@@ -99,9 +101,21 @@ test_buffer() {
if write_buffer 0xdeadbeef $size ; then
echo "Too big of write expected to fail but did not"
+ echo $ORIG > buffer_size_kb
exit_fail
fi
}
+ORIG=`cat buffer_size_kb`
+
+# test_multiple_writes test needs at least 12KB buffer
+NEW_SIZE=12
+
+if [ ${ORIG} -lt ${NEW_SIZE} ]; then
+ echo ${NEW_SIZE} > buffer_size_kb
+fi
+
test_buffer
test_multiple_writes
+
+echo $ORIG > buffer_size_kb
--
2.36.1
Much work has recently gone into supporting block device integrity data
(sometimes called "metadata") in Linux. Many NVMe devices these days
support metadata transfers and/or automatic protection information
generation and verification. However, ublk devices can't yet advertise
integrity data capabilities. This patch series wires up support for
integrity data in ublk. The ublk feature is referred to as "integrity"
rather than "metadata" to match the block layer's name for it and to
avoid confusion with the existing and unrelated UBLK_IO_F_META.
To advertise support for integrity data, a ublk server fills out the
struct ublk_params's integrity field and sets UBLK_PARAM_TYPE_INTEGRITY.
The struct ublk_param_integrity flags and csum_type fields use the
existing LBMD_PI_* constants from the linux/fs.h UAPI header. The ublk
driver fills out a corresponding struct blk_integrity.
When a request with integrity data is issued to the ublk device, the
ublk driver sets UBLK_IO_F_INTEGRITY in struct ublksrv_io_desc's
op_flags field. This is necessary for a ublk server for which
bi_offload_capable() returns true to distinguish requests with integrity
data from those without.
Integrity data transfers can currently only be performed via the ublk
user copy mechanism. The overhead of zero-copy buffer registration makes
it less appealing for the small transfers typical of integrity data.
Additionally, neither io_uring NVMe passthru nor IORING_RW_ATTR_FLAG_PI
currently allow an io_uring registered buffer for the integrity data.
The ki_pos field of the struct kiocb passed to the user copy
->{read,write}_iter() callback gains a bit UBLKSRV_IO_INTEGRITY_FLAG for
a ublk server to indicate whether to access the request's data or
integrity data.
Not yet supported is an analogue for the IO_INTEGRITY_CHK_*/BIP_CHECK_*
flags to ask the ublk server to verify the guard, reftag, and/or apptag
of a request's protection information. The user copy mechanism currently
forbids a ublk server from reading the data/integrity buffer of a
read-direction request. We could potentially relax this restriction for
integrity data on reads. Alternatively, the ublk driver could verify the
requested fields as part of the user copy operation.
The first 2 commits harden blk_validate_integrity_limits() to reject
nonsensical pi_offset and interval_exp integrity limits.
Caleb Sander Mateos (17):
block: validate pi_offset integrity limit
block: validate interval_exp integrity limit
blk-integrity: take const pointer in blk_integrity_rq()
ublk: move ublk flag check functions earlier
ublk: set UBLK_IO_F_INTEGRITY in ublksrv_io_desc
ublk: add ublk_copy_user_bvec() helper
ublk: split out ublk_user_copy() helper
ublk: inline ublk_check_and_get_req() into ublk_user_copy()
ublk: move offset check out of __ublk_check_and_get_req()
ublk: optimize ublk_user_copy() on daemon task
selftests: ublk: add utility to get block device metadata size
selftests: ublk: add kublk support for integrity params
selftests: ublk: implement integrity user copy in kublk
selftests: ublk: support non-O_DIRECT backing files
selftests: ublk: add integrity data support to loop target
selftests: ublk: add integrity params test
selftests: ublk: add end-to-end integrity test
Stanley Zhang (3):
ublk: add integrity UAPI
ublk: support UBLK_PARAM_TYPE_INTEGRITY in device creation
ublk: implement integrity user copy
block/blk-settings.c | 14 +-
drivers/block/ublk_drv.c | 336 +++++++++++++------
include/linux/blk-integrity.h | 6 +-
include/uapi/linux/ublk_cmd.h | 20 +-
tools/testing/selftests/ublk/Makefile | 6 +-
tools/testing/selftests/ublk/common.c | 4 +-
tools/testing/selftests/ublk/fault_inject.c | 1 +
tools/testing/selftests/ublk/file_backed.c | 61 +++-
tools/testing/selftests/ublk/kublk.c | 85 ++++-
tools/testing/selftests/ublk/kublk.h | 37 +-
tools/testing/selftests/ublk/metadata_size.c | 37 ++
tools/testing/selftests/ublk/null.c | 1 +
tools/testing/selftests/ublk/stripe.c | 6 +-
tools/testing/selftests/ublk/test_common.sh | 10 +
tools/testing/selftests/ublk/test_loop_08.sh | 111 ++++++
tools/testing/selftests/ublk/test_null_04.sh | 166 +++++++++
16 files changed, 765 insertions(+), 136 deletions(-)
create mode 100644 tools/testing/selftests/ublk/metadata_size.c
create mode 100755 tools/testing/selftests/ublk/test_loop_08.sh
create mode 100755 tools/testing/selftests/ublk/test_null_04.sh
--
2.45.2
In cgroup v2, a mutual overlap check is required when at least one of two
cpusets is exclusive. However, this check should be relaxed and limited to
cases where both cpusets are exclusive.
This patch ensures that for sibling cpusets A1 (exclusive) and B1
(non-exclusive), change B1 cannot affect A1's exclusivity.
for example. Assume a machine has 4 CPUs (0-3).
root cgroup
/ \
A1 B1
Case 1:
Table 1.1: Before applying the patch
Step | A1's prstate | B1'sprstate |
#1> echo "0-1" > A1/cpuset.cpus | member | member |
#2> echo "root" > A1/cpuset.cpus.partition | root | member |
#3> echo "0" > B1/cpuset.cpus | root invalid | member |
After step #3, A1 changes from "root" to "root invalid" because its CPUs
(0-1) overlap with those requested by B1 (0-3). However, B1 can actually
use CPUs 2-3(from B1's parent), so it would be more reasonable for A1 to
remain as "root."
Table 1.2: After applying the patch
Step | A1's prstate | B1'sprstate |
#1> echo "0-1" > A1/cpuset.cpus | member | member |
#2> echo "root" > A1/cpuset.cpus.partition | root | member |
#3> echo "0" > B1/cpuset.cpus | root | member |
Case 2: (This situation remains unchanged from before)
Table 2.1: Before applying the patch
Step | A1's prstate | B1'sprstate |
#1> echo "0-1" > A1/cpuset.cpus | member | member |
#3> echo "1-2" > B1/cpuset.cpus | member | member |
#2> echo "root" > A1/cpuset.cpus.partition | root invalid | member |
Table 2.2: After applying the patch
Step | A1's prstate | B1'sprstate |
#1> echo "0-1" > A1/cpuset.cpus | member | member |
#3> echo "1-2" > B1/cpuset.cpus | member | member |
#2> echo "root" > A1/cpuset.cpus.partition | root invalid | member |
All other cases remain unaffected. For example, cgroup-v1, both A1 and
B1 are exclusive or non-exlusive.
---
v3 -> v4:
- Adjust the test_cpuset_prt.sh test file to align with the current
behavior.
v2 -> v3:
- Ensure compliance with constraints such as cpuset.cpus.exclusive.
- Link: https://lore.kernel.org/cgroups/20251113131434.606961-1-sunshaojie@kylinos.…
v1 -> v2:
- Keeps the current cgroup v1 behavior unchanged
- Link: https://lore.kernel.org/cgroups/c8e234f4-2c27-4753-8f39-8ae83197efd3@redhat…
---
kernel/cgroup/cpuset-internal.h | 3 ++
kernel/cgroup/cpuset-v1.c | 20 +++++++++
kernel/cgroup/cpuset.c | 43 ++++++++++++++-----
.../selftests/cgroup/test_cpuset_prs.sh | 5 ++-
4 files changed, 58 insertions(+), 13 deletions(-)
--
2.25.1
Small clean up series to eliminate the extra includes of
<uapi/linux/types.h> from various VFIO selftests files. This include is
not causing any problems now, but it is causing benign typedef
redifinitions. Those redifinitions will become a problem when the VFIO
selftests library is built into KVM selftests, since KVM selftests build
with -std=gnu99.
Cc: Yosry Ahmed <yosryahmed(a)google.com>
Cc: Josh Hilke <jrhilke(a)google.com>
David Matlack (2):
tools include: Add definitions for __aligned_{l,b}e64
vfio: selftests: Drop <uapi/linux/types.h> includes
tools/include/linux/types.h | 8 ++++++++
.../selftests/vfio/lib/include/libvfio/iova_allocator.h | 1 -
tools/testing/selftests/vfio/lib/iommu.c | 1 -
tools/testing/selftests/vfio/lib/iova_allocator.c | 1 -
tools/testing/selftests/vfio/lib/vfio_pci_device.c | 1 -
tools/testing/selftests/vfio/vfio_dma_mapping_test.c | 1 -
tools/testing/selftests/vfio/vfio_iommufd_setup_test.c | 1 -
7 files changed, 8 insertions(+), 6 deletions(-)
base-commit: d721f52e31553a848e0e9947ca15a49c5674aef3
--
2.52.0.322.g1dd061c0dc-goog
This is the last remaining "Test Module" kselftest, the rest having been
converted to KUnit.
Relative to v1 this keeps benchmarks out of KUnit in light of Yury's
concerns:
On Sat, Feb 8, 2025 at 12:53 PM Yury Norov <yury.norov(a)gmail.com> wrote:
>
> [...]
>
> This is my evidence: sometimes people report performance or whatever
> issues on their systems, suspecting bitmaps guilty. I ask them to run
> the bitmap or find_bit test to narrow the problem. Sometimes I need to
> test a hardware I have no access to, and I have to (kindly!) ask
people
> to build a small test and run it. I don't want to ask them to rebuild
> the whole kernel, or even to build something else.
>
> https://lore.kernel.org/all/YuWk3titnOiQACzC@yury-laptop/
I tested this using:
$ tools/testing/kunit/kunit.py run --arch arm64 --make_options LLVM=1 bitmap
There was a previous attempt[2] to do this in July 2024. Please bear
with me as I try to understand and address the objections from that
time. I've spoken with Muhammad Usama Anjum, the author of that series,
and received their approval to "take over" this work. Here we go...
On 7/26/24 11:45 PM, John Hubbard wrote:
>
> This changes the situation from "works for Linus' tab completion
> case", to "causes a tab completion problem"! :)
>
> I think a tests/ subdir is how we eventually decided to do this [1],
> right?
>
> So:
>
> lib/tests/bitmap_kunit.c
>
> [1] https://lore.kernel.org/20240724201354.make.730-kees@kernel.org
This is true and unfortunate, but not trivial to fix because new
kallsyms tests were placed in lib/tests in commit 84b4a51fce4c
("selftests: add new kallsyms selftests") *after* the KUnit filename
best practices were adopted.
I propose that the KUnit maintainers blaze this trail using
`string_kunit.c` which currently still lives in lib/ despite the KUnit
docs giving it as an example at lib/tests/.
On 7/27/24 12:24 AM, Shuah Khan wrote:
>
> This change will take away the ability to run bitmap tests during
> boot on a non-kunit kernel.
>
> Nack on this change. I wan to see all tests that are being removed
> from lib because they have been converted - also it doesn't make
> sense to convert some tests like this one that add the ability test
> during boot.
This point was also discussed in another thread[3] in which:
On 7/27/24 12:35 AM, Shuah Khan wrote:
>
> Please make sure you aren't taking away the ability to run these tests during
> boot.
>
> It doesn't make sense to convert every single test especially when it
> is intended to be run during boot without dependencies - not as a kunit test
> but a regression test during boot.
>
> bitmap is one example - pay attention to the config help test - bitmap
> one clearly states it runs regression testing during boot. Any test that
> says that isn't a candidate for conversion.
>
> I am going to nack any such conversions.
The crux of the argument seems to be that the config help text is taken
to describe the author's intent with the fragment "at boot". I think
this may be a case of confirmation bias: I see at least the following
KUnit tests with "at boot" in their help text:
- CPUMASK_KUNIT_TEST
- BITFIELD_KUNIT
- CHECKSUM_KUNIT
- UTIL_MACROS_KUNIT
It seems to me that the inference being made is that any test that runs
"at boot" is intended to be run by both developers and users, but I find
no evidence that bitmap in particular would ever provide additional
value when run by users.
There's further discussion about KUnit not being "ideal for cases where
people would want to check a subsystem on a running kernel", but I find
no evidence that bitmap in particular is actually testing the running
kernel; it is a unit test of the bitmap functions, which is also stated
in the config help text.
David Gow made many of the same points in his final reply[4], which was
never replied to.
Link: https://lore.kernel.org/all/20250207-printf-kunit-convert-v2-0-057b23860823… [0]
Link: https://lore.kernel.org/all/20250207-scanf-kunit-convert-v4-0-a23e2afaede8@… [1]
Link: https://lore.kernel.org/all/20240726110658.2281070-1-usama.anjum@collabora.… [2]
Link: https://lore.kernel.org/all/327831fb-47ab-4555-8f0b-19a8dbcaacd7@collabora.… [3]
Link: https://lore.kernel.org/all/CABVgOSmMoPD3JfzVd4VTkzGL2fZCo8LfwzaVSzeFimPrhg… [4]
Thanks for your attention.
Signed-off-by: Tamir Duberstein <tamird(a)gmail.com>
---
Changes in v2:
- Rebase on v6.19-rc1, dropping the first patch.
- Extract benchmarks into new module and deduplicate
`test_bitmap_{read,write}_perf`.
- Remove tc_err() and use KUnit assertions.
- Parameterize `test_bitmap_cut` and `test_bitmap_parse{,list}`.
- Drop KUnit boilerplate from BITMAP_KUNIT_TEST help text.
- Drop arch changes.
- Link to v1: https://lore.kernel.org/r/20250207-bitmap-kunit-convert-v1-0-c520675343b6@g…
---
Tamir Duberstein (3):
test_bitmap: extract benchmark module
bitmap: convert self-test to KUnit
bitmap: break kunit into test cases
MAINTAINERS | 3 +-
lib/Kconfig.debug | 16 +-
lib/Makefile | 5 +-
lib/bitmap_benchmark.c | 89 +++++
lib/{test_bitmap.c => bitmap_kunit.c} | 630 ++++++++++++++--------------------
tools/testing/selftests/lib/Makefile | 2 +-
tools/testing/selftests/lib/bitmap.sh | 3 -
tools/testing/selftests/lib/config | 1 -
8 files changed, 360 insertions(+), 389 deletions(-)
---
base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8
change-id: 20250207-bitmap-kunit-convert-92d3147b2eee
Best regards,
--
Tamir Duberstein <tamird(a)gmail.com>
On Mon, 22 Dec 2025 09:45:41 +0800
Li Wang <liwang(a)redhat.com> wrote:
> On Mon, Dec 22, 2025 at 6:11 AM David Laight <david.laight.linux(a)gmail.com>
> wrote:
>
> > On Sun, 21 Dec 2025 20:26:37 +0800
> > Li Wang <liwang(a)redhat.com> wrote:
> >
> > > write_to_hugetlbfs currently parses the -s size argument with atoi()
> > > into an int. This silently accepts malformed input, cannot report
> > overflow,
> > > and can truncate large sizes.
> >
> > And sscanf() will just ignore invalid trailing characters.
> > Probably much the same as atoi() apart from a leading '-'.
> >
> > Maybe you could use "%zu%c" and check the count is 1 - but I bet
> > some static checker won't like that.
> >
>
> Yes, that would be stronger, since it would reject trailing garbage.
> But for a selftest this is probably sufficient: switching to size_t and
> parsing with "%zu" already avoids the int truncation issue.
Have you checked at what does sscanf() does with an overlong digit string?
I'd guess that it just processes all the digits and then masks the result
to fix (like the kernel one does).
It reality scanf() is 'not the function you are lookign for'.
IIRC the 'SUS' (used to) say that this was absolutely fine for command
line parsing for 'standard utilities'.
It is best to use strtoul() and check the 'end' character is '\0'.
David
>
> @Andrew Morton <akpm(a)linux-foundation.org>,
>
> Hi Andrew, I noticed you have addedthe patches to your mm-new branch,
> Let me know if you prefer the "%zu%c" enhancement in a new version.
>
>
Hi,
This series adds missing memory access tags (MEM_RDONLY or MEM_WRITE) to
several bpf helper function prototypes that use ARG_PTR_TO_MEM but lack the
correct type annotation.
Missing memory access tags in helper prototypes can lead to critical
correctness issues when the verifier tries to perform code optimization.
After commit 37cce22dbd51 ("bpf: verifier: Refactor helper access type
tracking"), the verifier relies on the memory access tags, rather than
treating all arguments in helper functions as potentially modifying the
pointed-to memory.
We have already seen several reports regarding this:
- commit ac44dcc788b9 ("bpf: Fix verifier assumptions of bpf_d_path's
output buffer") adds MEM_WRITE to bpf_d_path;
- commit 2eb7648558a7 ("bpf: Specify access type of bpf_sysctl_get_name
args") adds MEM_WRITE to bpf_sysctl_get_name.
This series looks through all prototypes in the kernel and completes the
tags. In addition, this series also adds selftests for some of these
functions.
I marked the series as RFC since the introduced selftests are fragile and
ad hoc (similar to the previously added selftests). The original goal of
these tests is to reproduce the case where the verifier wrongly optimizes
reads after the helper function is called. However, triggering the error
often requires carefully designed code patterns. For example, I had to
explicitly use "if (xx != 0)" in my attached tests, because using memcmp
will not reproduce the issue. This makes the reproduction heavily dependent
on the verifier's internal optimization logic and clutters the selftests
with specific, unnatural patterns.
Some cases are also hard to trigger by selftests. For example, I couldn't
find a triggering pattern for bpf_read_branch_records, since the
execution of program seems to be messed up by wrong tags. For
bpf_skb_fib_lookup, I also failed to reproduce it because the argument
needs content on entry, but the verifier seems to only enable this
optimization for fully empty buffers.
Since adding selftests does not help with existing issues or prevent future
occurrences of similar problems, I believe one way to resolve it is to
statically restrict ARG_PTR_TO_MEM from appearing without memory access
tags. Using ARG_PTR_TO_MEM alone without tags is nonsensical because:
- If the helper does not change the argument, missing MEM_RDONLY causes
the verifier to incorrectly reject a read-only buffer.
- If the helper does change the argument, missing MEM_WRITE causes the
verifier to incorrectly assume the memory is unchanged, leading to
potential errors.
I am still wondering, if we agree on the above, how should we enforce this
restriction? Should we let ARG_PTR_TO_MEM imply MEM_WRITE semantics by
default, and change ARG_PTR_TO_MEM | MEM_RDONLY to ARG_CONST_PTR_TO_MEM? Or
should we add a check in the verifier to ensure ARG_PTR_TO_MEM always comes
with an access tag (though this seems to only catch errors at
runtime/testing)?
Any insights and comments are welcome. If the individual fix patches for
the prototypes look correct, I would also really appreciate it if they
could be merged ahead of the discussion.
Thanks,
Zesen Liu
Signed-off-by: Zesen Liu <ftyghome(a)gmail.com>
---
Zesen Liu (2):
bpf: Fix memory access tags in helper prototypes
selftests/bpf: add regression tests for snprintf and get_stack helpers
kernel/bpf/helpers.c | 2 +-
kernel/trace/bpf_trace.c | 6 +++---
net/core/filter.c | 8 ++++----
tools/testing/selftests/bpf/prog_tests/get_stack_raw_tp.c | 15 +++++++++++++--
tools/testing/selftests/bpf/prog_tests/snprintf.c | 6 ++++++
tools/testing/selftests/bpf/prog_tests/snprintf_btf.c | 3 +++
tools/testing/selftests/bpf/progs/netif_receive_skb.c | 13 ++++++++++++-
tools/testing/selftests/bpf/progs/test_get_stack_rawtp.c | 11 ++++++++++-
tools/testing/selftests/bpf/progs/test_snprintf.c | 12 ++++++++++++
9 files changed, 64 insertions(+), 12 deletions(-)
---
base-commit: 22cc16c04b7893d8fc22810599f49a305d600b9e
change-id: 20251220-helper_proto-fb6e64182467
Best regards,
--
Zesen Liu <ftyghome(a)gmail.com>