* [PATCH v3 0/2] vfio: selftests: Add calloc_assert() and avoid VLAs
@ 2026-06-15 19:44 Alex Mastro
2026-06-15 19:44 ` [PATCH v3 1/2] vfio: selftests: Add calloc_assert() helper Alex Mastro
2026-06-15 19:44 ` [PATCH v3 2/2] vfio: selftests: Avoid VLAs Alex Mastro
0 siblings, 2 replies; 5+ messages in thread
From: Alex Mastro @ 2026-06-15 19:44 UTC (permalink / raw)
To: Alex Williamson, David Matlack, Shuah Khan,
Raghavendra Rao Ananta, Vipin Sharma
Cc: kvm, linux-kselftest, linux-kernel, Shuah Khan, Alex Mastro
Add a VFIO selftest calloc_assert() helper, then use it in places that
open-code calloc() or malloc() followed by VFIO_ASSERT_NOT_NULL().
Use that helper to replace initialized variable-length stack buffers in
vfio_pci_device.c with heap allocations. This avoids GCC rejecting
initialized VLAs and avoids treating a u8 buffer as a possibly
under-aligned VFIO request struct.
Changes in v3:
- Add the calloc_assert() helper as a precursor patch.
- Convert existing VFIO selftest calloc() assertion sites.
- Update the VLA fix to use calloc_assert().
- Link to v2: https://patch.msgid.link/20260615-scratch-amastro-vfio-selftests-avoid-vlas-v2-1-4e4df462908a@fb.com
Changes in v2:
- Reverse xmas tree variable ordering
- Link to v1: https://patch.msgid.link/20260612-scratch-amastro-vfio-selftests-avoid-vlas-v1-1-ba3acb635f0a@fb.com
Signed-off-by: Alex Mastro <amastro@fb.com>
---
Alex Mastro (2):
vfio: selftests: Add calloc_assert() helper
vfio: selftests: Avoid VLAs
.../selftests/vfio/lib/include/libvfio/assert.h | 10 +++++++
tools/testing/selftests/vfio/lib/iommu.c | 12 +++-----
tools/testing/selftests/vfio/lib/iova_allocator.c | 4 +--
tools/testing/selftests/vfio/lib/sysfs.c | 3 +-
tools/testing/selftests/vfio/lib/vfio_pci_device.c | 32 ++++++++++++----------
.../vfio/vfio_pci_device_init_perf_test.c | 4 +--
6 files changed, 35 insertions(+), 30 deletions(-)
---
base-commit: a26b499b757cfc8bbff1088bb1b844639e250893
change-id: 20260612-scratch-amastro-vfio-selftests-avoid-vlas-395eb3dcb3ab
Best regards,
--
Alex Mastro <amastro@fb.com>
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH v3 1/2] vfio: selftests: Add calloc_assert() helper 2026-06-15 19:44 [PATCH v3 0/2] vfio: selftests: Add calloc_assert() and avoid VLAs Alex Mastro @ 2026-06-15 19:44 ` Alex Mastro 2026-06-15 22:51 ` David Matlack 2026-06-15 19:44 ` [PATCH v3 2/2] vfio: selftests: Avoid VLAs Alex Mastro 1 sibling, 1 reply; 5+ messages in thread From: Alex Mastro @ 2026-06-15 19:44 UTC (permalink / raw) To: Alex Williamson, David Matlack, Shuah Khan, Raghavendra Rao Ananta, Vipin Sharma Cc: kvm, linux-kselftest, linux-kernel, Shuah Khan, Alex Mastro Add a calloc_assert() helper alongside the existing ioctl_assert() and snprintf_assert() helpers. Use it for VFIO selftest allocations that immediately assert a non-NULL result. Assisted-by: Codex:gpt-5.5-high Signed-off-by: Alex Mastro <amastro@fb.com> --- tools/testing/selftests/vfio/lib/include/libvfio/assert.h | 10 ++++++++++ tools/testing/selftests/vfio/lib/iommu.c | 12 ++++-------- tools/testing/selftests/vfio/lib/iova_allocator.c | 4 +--- tools/testing/selftests/vfio/lib/sysfs.c | 3 +-- tools/testing/selftests/vfio/lib/vfio_pci_device.c | 6 ++---- .../testing/selftests/vfio/vfio_pci_device_init_perf_test.c | 4 ++-- 6 files changed, 20 insertions(+), 19 deletions(-) diff --git a/tools/testing/selftests/vfio/lib/include/libvfio/assert.h b/tools/testing/selftests/vfio/lib/include/libvfio/assert.h index 77b68c7129a6..f0490a403826 100644 --- a/tools/testing/selftests/vfio/lib/include/libvfio/assert.h +++ b/tools/testing/selftests/vfio/lib/include/libvfio/assert.h @@ -3,6 +3,7 @@ #define SELFTESTS_VFIO_LIB_INCLUDE_LIBVFIO_ASSERT_H #include <stdio.h> +#include <stdlib.h> #include <string.h> #include <sys/ioctl.h> @@ -45,6 +46,15 @@ VFIO_LOG_AND_EXIT(_fmt, ##__VA_ARGS__); \ } while (0) +#define calloc_assert(_nmemb, _size) ({ \ + size_t __nmemb = (_nmemb); \ + size_t __size = (_size); \ + void *__ptr = calloc(__nmemb, __size); \ + VFIO_ASSERT_NOT_NULL(__ptr, "calloc(%zu, %zu) failed", \ + __nmemb, __size); \ + __ptr; \ +}) + #define ioctl_assert(_fd, _op, _arg) do { \ void *__arg = (_arg); \ int __ret = ioctl((_fd), (_op), (__arg)); \ diff --git a/tools/testing/selftests/vfio/lib/iommu.c b/tools/testing/selftests/vfio/lib/iommu.c index 035dac069d60..31aba9fda8e5 100644 --- a/tools/testing/selftests/vfio/lib/iommu.c +++ b/tools/testing/selftests/vfio/lib/iommu.c @@ -286,8 +286,7 @@ static struct vfio_iommu_type1_info *vfio_iommu_get_info(int container_fd) { struct vfio_iommu_type1_info *info; - info = malloc(sizeof(*info)); - VFIO_ASSERT_NOT_NULL(info); + info = calloc_assert(1, sizeof(*info)); *info = (struct vfio_iommu_type1_info) { .argsz = sizeof(*info), @@ -324,8 +323,7 @@ static struct iommu_iova_range *vfio_iommu_iova_ranges(struct iommu *iommu, cap_range = container_of(hdr, struct vfio_iommu_type1_info_cap_iova_range, header); VFIO_ASSERT_GT(cap_range->nr_iovas, 0); - ranges = calloc(cap_range->nr_iovas, sizeof(*ranges)); - VFIO_ASSERT_NOT_NULL(ranges); + ranges = calloc_assert(cap_range->nr_iovas, sizeof(*ranges)); for (u32 i = 0; i < cap_range->nr_iovas; i++) { ranges[i] = (struct iommu_iova_range){ @@ -357,8 +355,7 @@ static struct iommu_iova_range *iommufd_iova_ranges(struct iommu *iommu, VFIO_ASSERT_EQ(errno, EMSGSIZE); VFIO_ASSERT_GT(query.num_iovas, 0); - ranges = calloc(query.num_iovas, sizeof(*ranges)); - VFIO_ASSERT_NOT_NULL(ranges); + ranges = calloc_assert(query.num_iovas, sizeof(*ranges)); query.allowed_iovas = (uintptr_t)ranges; @@ -424,8 +421,7 @@ struct iommu *iommu_init(const char *iommu_mode) struct iommu *iommu; int version; - iommu = calloc(1, sizeof(*iommu)); - VFIO_ASSERT_NOT_NULL(iommu); + iommu = calloc_assert(1, sizeof(*iommu)); INIT_LIST_HEAD(&iommu->dma_regions); diff --git a/tools/testing/selftests/vfio/lib/iova_allocator.c b/tools/testing/selftests/vfio/lib/iova_allocator.c index 8c1cc86b70cd..2e7d54e1b4c6 100644 --- a/tools/testing/selftests/vfio/lib/iova_allocator.c +++ b/tools/testing/selftests/vfio/lib/iova_allocator.c @@ -29,8 +29,7 @@ struct iova_allocator *iova_allocator_init(struct iommu *iommu) ranges = iommu_iova_ranges(iommu, &nranges); VFIO_ASSERT_NOT_NULL(ranges); - allocator = malloc(sizeof(*allocator)); - VFIO_ASSERT_NOT_NULL(allocator); + allocator = calloc_assert(1, sizeof(*allocator)); *allocator = (struct iova_allocator){ .ranges = ranges, @@ -90,4 +89,3 @@ iova_t iova_allocator_alloc(struct iova_allocator *allocator, size_t size) allocator->range_offset = 0; } } - diff --git a/tools/testing/selftests/vfio/lib/sysfs.c b/tools/testing/selftests/vfio/lib/sysfs.c index 11415448b2e2..98a46a2543cd 100644 --- a/tools/testing/selftests/vfio/lib/sysfs.c +++ b/tools/testing/selftests/vfio/lib/sysfs.c @@ -107,8 +107,7 @@ char *sysfs_sriov_vf_bdf_get(const char *pf_bdf, int i) char *out_vf_bdf; /* Fit "0000:00:00.0" */ - out_vf_bdf = calloc(16, sizeof(char)); - VFIO_ASSERT_NOT_NULL(out_vf_bdf); + out_vf_bdf = calloc_assert(16, sizeof(char)); snprintf_assert(path, PATH_MAX, "/sys/bus/pci/devices/%s/virtfn%d", pf_bdf, i); readlink_base(path, "%s", out_vf_bdf); diff --git a/tools/testing/selftests/vfio/lib/vfio_pci_device.c b/tools/testing/selftests/vfio/lib/vfio_pci_device.c index 94dc5fcecbeb..eb40f7159bae 100644 --- a/tools/testing/selftests/vfio/lib/vfio_pci_device.c +++ b/tools/testing/selftests/vfio/lib/vfio_pci_device.c @@ -343,8 +343,7 @@ const char *vfio_pci_get_cdev_path(const char *bdf) char *cdev_path; DIR *dir; - cdev_path = calloc(PATH_MAX, 1); - VFIO_ASSERT_NOT_NULL(cdev_path); + cdev_path = calloc_assert(PATH_MAX, 1); snprintf_assert(dir_path, sizeof(dir_path), "/sys/bus/pci/devices/%s/vfio-dev/", bdf); @@ -425,8 +424,7 @@ struct vfio_pci_device *vfio_pci_device_alloc(const char *bdf, struct iommu *iom { struct vfio_pci_device *device; - device = calloc(1, sizeof(*device)); - VFIO_ASSERT_NOT_NULL(device); + device = calloc_assert(1, sizeof(*device)); VFIO_ASSERT_NOT_NULL(iommu); device->iommu = iommu; diff --git a/tools/testing/selftests/vfio/vfio_pci_device_init_perf_test.c b/tools/testing/selftests/vfio/vfio_pci_device_init_perf_test.c index 33b0c31fe2ed..e1a54e153cd3 100644 --- a/tools/testing/selftests/vfio/vfio_pci_device_init_perf_test.c +++ b/tools/testing/selftests/vfio/vfio_pci_device_init_perf_test.c @@ -45,8 +45,8 @@ FIXTURE_SETUP(vfio_pci_device_init_perf_test) int i; self->iommu = iommu_init(variant->iommu_mode); - self->threads = calloc(nr_devices, sizeof(self->threads[0])); - self->thread_args = calloc(nr_devices, sizeof(self->thread_args[0])); + self->threads = calloc_assert(nr_devices, sizeof(self->threads[0])); + self->thread_args = calloc_assert(nr_devices, sizeof(self->thread_args[0])); pthread_barrier_init(&self->barrier, NULL, nr_devices); -- 2.53.0-Meta ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v3 1/2] vfio: selftests: Add calloc_assert() helper 2026-06-15 19:44 ` [PATCH v3 1/2] vfio: selftests: Add calloc_assert() helper Alex Mastro @ 2026-06-15 22:51 ` David Matlack 0 siblings, 0 replies; 5+ messages in thread From: David Matlack @ 2026-06-15 22:51 UTC (permalink / raw) To: Alex Mastro Cc: Alex Williamson, Shuah Khan, Raghavendra Rao Ananta, Vipin Sharma, kvm, linux-kselftest, linux-kernel, Shuah Khan On Mon, Jun 15, 2026 at 12:45 PM Alex Mastro <amastro@fb.com> wrote: > > Add a calloc_assert() helper alongside the existing ioctl_assert() and > snprintf_assert() helpers. > > Use it for VFIO selftest allocations that immediately assert a > non-NULL result. > > Assisted-by: Codex:gpt-5.5-high > Signed-off-by: Alex Mastro <amastro@fb.com> > --- > tools/testing/selftests/vfio/lib/include/libvfio/assert.h | 10 ++++++++++ > tools/testing/selftests/vfio/lib/iommu.c | 12 ++++-------- > tools/testing/selftests/vfio/lib/iova_allocator.c | 4 +--- > tools/testing/selftests/vfio/lib/sysfs.c | 3 +-- > tools/testing/selftests/vfio/lib/vfio_pci_device.c | 6 ++---- > .../testing/selftests/vfio/vfio_pci_device_init_perf_test.c | 4 ++-- > 6 files changed, 20 insertions(+), 19 deletions(-) > > diff --git a/tools/testing/selftests/vfio/lib/include/libvfio/assert.h b/tools/testing/selftests/vfio/lib/include/libvfio/assert.h > index 77b68c7129a6..f0490a403826 100644 > --- a/tools/testing/selftests/vfio/lib/include/libvfio/assert.h > +++ b/tools/testing/selftests/vfio/lib/include/libvfio/assert.h > @@ -3,6 +3,7 @@ > #define SELFTESTS_VFIO_LIB_INCLUDE_LIBVFIO_ASSERT_H > > #include <stdio.h> > +#include <stdlib.h> > #include <string.h> > #include <sys/ioctl.h> > > @@ -45,6 +46,15 @@ > VFIO_LOG_AND_EXIT(_fmt, ##__VA_ARGS__); \ > } while (0) > > +#define calloc_assert(_nmemb, _size) ({ \ > + size_t __nmemb = (_nmemb); \ > + size_t __size = (_size); \ > + void *__ptr = calloc(__nmemb, __size); \ > + VFIO_ASSERT_NOT_NULL(__ptr, "calloc(%zu, %zu) failed", \ > + __nmemb, __size); \ > + __ptr; \ > +}) > + > #define ioctl_assert(_fd, _op, _arg) do { \ > void *__arg = (_arg); \ > int __ret = ioctl((_fd), (_op), (__arg)); \ > diff --git a/tools/testing/selftests/vfio/lib/iommu.c b/tools/testing/selftests/vfio/lib/iommu.c > index 035dac069d60..31aba9fda8e5 100644 > --- a/tools/testing/selftests/vfio/lib/iommu.c > +++ b/tools/testing/selftests/vfio/lib/iommu.c > @@ -286,8 +286,7 @@ static struct vfio_iommu_type1_info *vfio_iommu_get_info(int container_fd) > { > struct vfio_iommu_type1_info *info; > > - info = malloc(sizeof(*info)); > - VFIO_ASSERT_NOT_NULL(info); > + info = calloc_assert(1, sizeof(*info)); > > *info = (struct vfio_iommu_type1_info) { > .argsz = sizeof(*info), > @@ -324,8 +323,7 @@ static struct iommu_iova_range *vfio_iommu_iova_ranges(struct iommu *iommu, > cap_range = container_of(hdr, struct vfio_iommu_type1_info_cap_iova_range, header); > VFIO_ASSERT_GT(cap_range->nr_iovas, 0); > > - ranges = calloc(cap_range->nr_iovas, sizeof(*ranges)); > - VFIO_ASSERT_NOT_NULL(ranges); > + ranges = calloc_assert(cap_range->nr_iovas, sizeof(*ranges)); > > for (u32 i = 0; i < cap_range->nr_iovas; i++) { > ranges[i] = (struct iommu_iova_range){ > @@ -357,8 +355,7 @@ static struct iommu_iova_range *iommufd_iova_ranges(struct iommu *iommu, > VFIO_ASSERT_EQ(errno, EMSGSIZE); > VFIO_ASSERT_GT(query.num_iovas, 0); > > - ranges = calloc(query.num_iovas, sizeof(*ranges)); > - VFIO_ASSERT_NOT_NULL(ranges); > + ranges = calloc_assert(query.num_iovas, sizeof(*ranges)); > > query.allowed_iovas = (uintptr_t)ranges; > > @@ -424,8 +421,7 @@ struct iommu *iommu_init(const char *iommu_mode) > struct iommu *iommu; > int version; > > - iommu = calloc(1, sizeof(*iommu)); > - VFIO_ASSERT_NOT_NULL(iommu); > + iommu = calloc_assert(1, sizeof(*iommu)); > > INIT_LIST_HEAD(&iommu->dma_regions); > > diff --git a/tools/testing/selftests/vfio/lib/iova_allocator.c b/tools/testing/selftests/vfio/lib/iova_allocator.c > index 8c1cc86b70cd..2e7d54e1b4c6 100644 > --- a/tools/testing/selftests/vfio/lib/iova_allocator.c > +++ b/tools/testing/selftests/vfio/lib/iova_allocator.c > @@ -29,8 +29,7 @@ struct iova_allocator *iova_allocator_init(struct iommu *iommu) > ranges = iommu_iova_ranges(iommu, &nranges); > VFIO_ASSERT_NOT_NULL(ranges); > > - allocator = malloc(sizeof(*allocator)); > - VFIO_ASSERT_NOT_NULL(allocator); > + allocator = calloc_assert(1, sizeof(*allocator)); Did you mean to replace malloc() with calloc()? Feel free to add a malloc_assert(). > > *allocator = (struct iova_allocator){ > .ranges = ranges, > @@ -90,4 +89,3 @@ iova_t iova_allocator_alloc(struct iova_allocator *allocator, size_t size) > allocator->range_offset = 0; > } > } > - > diff --git a/tools/testing/selftests/vfio/lib/sysfs.c b/tools/testing/selftests/vfio/lib/sysfs.c > index 11415448b2e2..98a46a2543cd 100644 > --- a/tools/testing/selftests/vfio/lib/sysfs.c > +++ b/tools/testing/selftests/vfio/lib/sysfs.c > @@ -107,8 +107,7 @@ char *sysfs_sriov_vf_bdf_get(const char *pf_bdf, int i) > char *out_vf_bdf; > > /* Fit "0000:00:00.0" */ > - out_vf_bdf = calloc(16, sizeof(char)); > - VFIO_ASSERT_NOT_NULL(out_vf_bdf); > + out_vf_bdf = calloc_assert(16, sizeof(char)); > > snprintf_assert(path, PATH_MAX, "/sys/bus/pci/devices/%s/virtfn%d", pf_bdf, i); > readlink_base(path, "%s", out_vf_bdf); > diff --git a/tools/testing/selftests/vfio/lib/vfio_pci_device.c b/tools/testing/selftests/vfio/lib/vfio_pci_device.c > index 94dc5fcecbeb..eb40f7159bae 100644 > --- a/tools/testing/selftests/vfio/lib/vfio_pci_device.c > +++ b/tools/testing/selftests/vfio/lib/vfio_pci_device.c > @@ -343,8 +343,7 @@ const char *vfio_pci_get_cdev_path(const char *bdf) > char *cdev_path; > DIR *dir; > > - cdev_path = calloc(PATH_MAX, 1); > - VFIO_ASSERT_NOT_NULL(cdev_path); > + cdev_path = calloc_assert(PATH_MAX, 1); > > snprintf_assert(dir_path, sizeof(dir_path), "/sys/bus/pci/devices/%s/vfio-dev/", bdf); > > @@ -425,8 +424,7 @@ struct vfio_pci_device *vfio_pci_device_alloc(const char *bdf, struct iommu *iom > { > struct vfio_pci_device *device; > > - device = calloc(1, sizeof(*device)); > - VFIO_ASSERT_NOT_NULL(device); > + device = calloc_assert(1, sizeof(*device)); > > VFIO_ASSERT_NOT_NULL(iommu); > device->iommu = iommu; > diff --git a/tools/testing/selftests/vfio/vfio_pci_device_init_perf_test.c b/tools/testing/selftests/vfio/vfio_pci_device_init_perf_test.c > index 33b0c31fe2ed..e1a54e153cd3 100644 > --- a/tools/testing/selftests/vfio/vfio_pci_device_init_perf_test.c > +++ b/tools/testing/selftests/vfio/vfio_pci_device_init_perf_test.c > @@ -45,8 +45,8 @@ FIXTURE_SETUP(vfio_pci_device_init_perf_test) > int i; > > self->iommu = iommu_init(variant->iommu_mode); > - self->threads = calloc(nr_devices, sizeof(self->threads[0])); > - self->thread_args = calloc(nr_devices, sizeof(self->thread_args[0])); > + self->threads = calloc_assert(nr_devices, sizeof(self->threads[0])); > + self->thread_args = calloc_assert(nr_devices, sizeof(self->thread_args[0])); > > pthread_barrier_init(&self->barrier, NULL, nr_devices); > > > -- > 2.53.0-Meta > ^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v3 2/2] vfio: selftests: Avoid VLAs 2026-06-15 19:44 [PATCH v3 0/2] vfio: selftests: Add calloc_assert() and avoid VLAs Alex Mastro 2026-06-15 19:44 ` [PATCH v3 1/2] vfio: selftests: Add calloc_assert() helper Alex Mastro @ 2026-06-15 19:44 ` Alex Mastro 2026-06-15 22:56 ` David Matlack 1 sibling, 1 reply; 5+ messages in thread From: Alex Mastro @ 2026-06-15 19:44 UTC (permalink / raw) To: Alex Williamson, David Matlack, Shuah Khan, Raghavendra Rao Ananta, Vipin Sharma Cc: kvm, linux-kselftest, linux-kernel, Shuah Khan, Alex Mastro Allocate VFIO ioctl requests dynamically instead of using VLAs. GCC 11.5.0 rejects initialized VLAs with: error: variable-sized object may not be initialized The replaced stack u8 arrays also do not guarantee native struct alignment for the aliased pointers. Fixes: 19faf6fd969c ("vfio: selftests: Add a helper library for VFIO selftests") Fixes: 20face8c75ff ("vfio: selftests: Add helper to set/override a vf_token") Assisted-by: Codex:gpt-5.5-high Reviewed-by: Vipin Sharma <vipinsh@google.com> Signed-off-by: Alex Mastro <amastro@fb.com> --- tools/testing/selftests/vfio/lib/vfio_pci_device.c | 26 +++++++++++++--------- 1 file changed, 15 insertions(+), 11 deletions(-) diff --git a/tools/testing/selftests/vfio/lib/vfio_pci_device.c b/tools/testing/selftests/vfio/lib/vfio_pci_device.c index eb40f7159bae..28868343f2ab 100644 --- a/tools/testing/selftests/vfio/lib/vfio_pci_device.c +++ b/tools/testing/selftests/vfio/lib/vfio_pci_device.c @@ -30,13 +30,11 @@ static void vfio_pci_irq_set(struct vfio_pci_device *device, u32 index, u32 vector, u32 count, int *fds) { - u8 buf[sizeof(struct vfio_irq_set) + sizeof(int) * count]; - struct vfio_irq_set *irq = (void *)&buf; - int *irq_fds = (void *)&irq->data; + size_t argsz = sizeof(struct vfio_irq_set) + sizeof(int) * count; + struct vfio_irq_set *irq; - memset(buf, 0, sizeof(buf)); - - irq->argsz = sizeof(buf); + irq = calloc_assert(1, argsz); + irq->argsz = argsz; irq->flags = VFIO_IRQ_SET_ACTION_TRIGGER; irq->index = index; irq->start = vector; @@ -44,12 +42,13 @@ static void vfio_pci_irq_set(struct vfio_pci_device *device, if (count) { irq->flags |= VFIO_IRQ_SET_DATA_EVENTFD; - memcpy(irq_fds, fds, sizeof(int) * count); + memcpy(irq->data, fds, sizeof(int) * count); } else { irq->flags |= VFIO_IRQ_SET_DATA_NONE; } ioctl_assert(device->fd, VFIO_DEVICE_SET_IRQS, irq); + free(irq); } void vfio_pci_irq_trigger(struct vfio_pci_device *device, u32 index, u32 vector) @@ -118,15 +117,20 @@ static void vfio_pci_irq_get(struct vfio_pci_device *device, u32 index, static int vfio_device_feature_ioctl(int fd, u32 flags, void *data, size_t data_size) { - u8 buffer[sizeof(struct vfio_device_feature) + data_size] = {}; - struct vfio_device_feature *feature = (void *)buffer; + size_t argsz = sizeof(struct vfio_device_feature) + data_size; + struct vfio_device_feature *feature; + int ret; + feature = calloc_assert(1, argsz); memcpy(feature->data, data, data_size); - feature->argsz = sizeof(buffer); + feature->argsz = argsz; feature->flags = flags; - return ioctl(fd, VFIO_DEVICE_FEATURE, feature); + ret = ioctl(fd, VFIO_DEVICE_FEATURE, feature); + free(feature); + + return ret; } static void vfio_device_feature_set(int fd, u16 feature, void *data, size_t data_size) -- 2.53.0-Meta ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v3 2/2] vfio: selftests: Avoid VLAs 2026-06-15 19:44 ` [PATCH v3 2/2] vfio: selftests: Avoid VLAs Alex Mastro @ 2026-06-15 22:56 ` David Matlack 0 siblings, 0 replies; 5+ messages in thread From: David Matlack @ 2026-06-15 22:56 UTC (permalink / raw) To: Alex Mastro Cc: Alex Williamson, Shuah Khan, Raghavendra Rao Ananta, Vipin Sharma, kvm, linux-kselftest, linux-kernel, Shuah Khan On 2026-06-15 12:44 PM, Alex Mastro wrote: > Allocate VFIO ioctl requests dynamically instead of using VLAs. GCC 11.5.0 > rejects initialized VLAs with: > > error: variable-sized object may not be initialized > > The replaced stack u8 arrays also do not guarantee native struct alignment > for the aliased pointers. > > Fixes: 19faf6fd969c ("vfio: selftests: Add a helper library for VFIO selftests") > Fixes: 20face8c75ff ("vfio: selftests: Add helper to set/override a vf_token") > Assisted-by: Codex:gpt-5.5-high > Reviewed-by: Vipin Sharma <vipinsh@google.com> > Signed-off-by: Alex Mastro <amastro@fb.com> Reviewed-by: David Matlack <dmatlack@google.com> ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2026-06-15 22:56 UTC | newest] Thread overview: 5+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2026-06-15 19:44 [PATCH v3 0/2] vfio: selftests: Add calloc_assert() and avoid VLAs Alex Mastro 2026-06-15 19:44 ` [PATCH v3 1/2] vfio: selftests: Add calloc_assert() helper Alex Mastro 2026-06-15 22:51 ` David Matlack 2026-06-15 19:44 ` [PATCH v3 2/2] vfio: selftests: Avoid VLAs Alex Mastro 2026-06-15 22:56 ` David Matlack
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