- 03 Mar, 2020 10 commits
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Andrii Nakryiko authored
Add selftests validating link pinning/unpinning and associated BPF link (attachment) lifetime. Signed-off-by:
Andrii Nakryiko <andriin@fb.com> Signed-off-by:
Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200303043159.323675-4-andriin@fb.com
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Andrii Nakryiko authored
With bpf_link abstraction supported by kernel explicitly, add pinning/unpinning API for links. Also allow to create (open) bpf_link from BPF FS file. This API allows to have an "ephemeral" FD-based BPF links (like raw tracepoint or fexit/freplace attachments) surviving user process exit, by pinning them in a BPF FS, which is an important use case for long-running BPF programs. As part of this, expose underlying FD for bpf_link. While legacy bpf_link's might not have a FD associated with them (which will be expressed as a bpf_link with fd=-1), kernel's abstraction is based around FD-based usage, so match it closely. This, subsequently, allows to have a generic pinning/unpinning API for generalized bpf_link. For some types of bpf_links kernel might not support pinning, in which case bpf_link__pin() will return error. With FD being part of generic bpf_link, also get rid of bpf_link_fd in favor of using vanialla bpf_link. Signed-off-by:
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Andrii Nakryiko authored
Introduce bpf_link abstraction, representing an attachment of BPF program to a BPF hook point (e.g., tracepoint, perf event, etc). bpf_link encapsulates ownership of attached BPF program, reference counting of a link itself, when reference from multiple anonymous inodes, as well as ensures that release callback will be called from a process context, so that users can safely take mutex locks and sleep. Additionally, with a new abstraction it's now possible to generalize pinning of a link object in BPF FS, allowing to explicitly prevent BPF program detachment on process exit by pinning it in a BPF FS and let it open from independent other process to keep working with it. Convert two existing bpf_link-like objects (raw tracepoint and tracing BPF program attachments) into utilizing bpf_link framework, making them pinnable in BPF FS. More FD-based bpf_links will be added in follow up patches. Signed-off-by:
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Toke Høiland-Jørgensen authored
The cgroup selftests did not declare the bpf_log_buf variable as static, leading to a linker error with GCC 10 (which defaults to -fno-common). Fix this by adding the missing static declarations. Fixes: 257c8855 ("selftests/bpf: Convert test_cgroup_attach to prog_tests") Signed-off-by:
Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by:
Andrey Ignatov <rdna@fb.com> Link: https://lore.kernel.org/bpf/20200302145348.559177-1-toke@redhat.com
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Andrii Nakryiko authored
btf_trace_xxx types, crucial for tp_btf BPF programs (raw tracepoint with verifier-checked direct memory access), have to be preserved in kernel BTF to allow verifier do its job and enforce type/memory safety. It was reported ([0]) that for kernels built with Clang current type-casting approach doesn't preserve these types. This patch fixes it by declaring an anonymous union for each registered tracepoint, capturing both struct bpf_raw_event_map information, as well as recording btf_trace_##call type reliably. Structurally, it's still the same content as for a plain struct bpf_raw_event_map, so no other changes are necessary. [0] https://github.com/iovisor/bcc/issues/2770#issuecomment-591007692 Fixes: e8c423fb ("bpf: Add typecast to raw_tracepoints to help BTF generation") Reported-by:
Wenbo Zhang <ethercflow@gmail.com> Signed-off-by:
Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200301081045.3491005-2-andriin@fb.com
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Alexei Starovoitov authored
Andrii Nakryiko says: ==================== Move BPF_PROG, BPF_KPROBE, and BPF_KRETPROBE helper macros from private selftests helpers to public libbpf ones. These helpers are extremely helpful for writing tracing BPF applications and have been requested to be exposed for easy use (e.g., [0]). As part of this move, fix up BPF_KRETPROBE to not allow for capturing input arguments (as it's unreliable and they will be often clobbered). Also, add vmlinux.h header guard to allow multi-time inclusion, if necessary; but also to let PT_REGS_PARM do proper detection of struct pt_regs field names on x86 arch. See relevant patches for more details. [0] https://github.com/iovisor/bcc/pull/2778#issue-381642907 ==================== Signed-off-by:
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Andrii Nakryiko authored
Move BPF_PROG, BPF_KPROBE, and BPF_KRETPROBE macro into libbpf's bpf_tracing.h header to make it available for non-selftests users. Signed-off-by:
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Andrii Nakryiko authored
For kretprobes, there is no point in capturing input arguments from pt_regs, as they are going to be, most probably, clobbered by the time probed kernel function returns. So switch BPF_KRETPROBE to accept zero or one argument (optional return result). Fixes: ac065870 ("selftests/bpf: Add BPF_PROG, BPF_KPROBE, and BPF_KRETPROBE macros") Signed-off-by:
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Andrii Nakryiko authored
Add detection of vmlinux.h to bpf_tracing.h header for PT_REGS macro. Currently, BPF applications have to define __KERNEL__ symbol to use correct definition of struct pt_regs on x86 arch. This is due to different field names under internal kernel vs UAPI conditions. To make this more transparent for users, detect vmlinux.h by checking __VMLINUX_H__ symbol. Signed-off-by:
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Andrii Nakryiko authored
Add canonical #ifndef/#define/#endif guard for generated vmlinux.h header with __VMLINUX_H__ symbol. __VMLINUX_H__ is also going to play double role of identifying whether vmlinux.h is being used, versus, say, BCC or non-CO-RE libbpf modes with dependency on kernel headers. This will make it possible to write helper macro/functions, agnostic to exact BPF program set up. Signed-off-by:
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- 02 Mar, 2020 25 commits
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Jesper Dangaard Brouer authored
Adding ethtool stats for when XDP transmitted packets overrun the TX queue. This is recorded separately for XDP_TX and ndo_xdp_xmit. This is an important aid for troubleshooting XDP based setups. It is currently a known weakness and property of XDP that there isn't any push-back or congestion feedback when transmitting frames via XDP. It's easy to realise when redirecting from a higher speed link into a slower speed link, or simply two ingress links into a single egress. The situation can also happen when Ethernet flow control is active. For testing the patch and provoking the situation to occur on my Espressobin board, I configured the TX-queue to be smaller (434) than RX-queue (512) and overload network with large MTU size frames (as a larger frame takes longer to transmit). Hopefully the upcoming XDP TX hook can be extended to provide insight into these TX queue overflows, to allow programmable adaptation strategies. Signed-off-by:
Jesper Dangaard Brouer <brouer@redhat.com> Acked-by:
Lorenzo Bianconi <lorenzo@kernel.org> Signed-off-by:
David S. Miller <davem@davemloft.net>
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David S. Miller authored
More zero-length array transformations from Gustavo A. R. Silva. Signed-off-by: -
Gustavo A. R. Silva authored
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by:Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by:
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Gustavo A. R. Silva authored
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: -
Gustavo A. R. Silva authored
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: -
Gustavo A. R. Silva authored
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: -
Gustavo A. R. Silva authored
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: -
Gustavo A. R. Silva authored
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: -
Gustavo A. R. Silva authored
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: -
Gustavo A. R. Silva authored
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: -
Gustavo A. R. Silva authored
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: -
Gustavo A. R. Silva authored
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: -
David S. Miller authored
Sunil Goutham says: ==================== net: thunderx: Miscellaneous changes This patchset has changes wrt driver performance optimization, load time optimization. And a change to PCI device regiatration table for timestamp device. ==================== Signed-off-by: -
Prakash Brahmajyosyula authored
Across Cavium's ThunderX and Marvell's OcteonTx2 silicons the PTP timestamping block's PCI device ID and vendor ID have remained same but the HW architecture has changed. Hence added PCI subsystem IDs to the device table to avoid this driver from being probed on OcteonTx2 silicons. Signed-off-by:
Prakash Brahmajyosyula <bprakash@marvell.com> Signed-off-by:
Sunil Goutham <sgoutham@marvell.com> Signed-off-by:
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Geetha sowjanya authored
Replace msleep() with usleep_range() as internally it uses hrtimers. This will put a cap on maximum wait time. Signed-off-by:
Geetha sowjanya <gakula@marvell.com> Signed-off-by:
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Sunil Goutham authored
With the current RX RED/DROP levels of 192/184 for CQE_RX, when packet incoming rate is high, LLC is getting polluted resulting in more cache misses and higher latency in packet processing. This slows down the whole process and performance loss. Hence reduced the levels to 224/216 (ie for a CQ size of 1024, Rx pkts will be red dropped or dropped when unused CQE are less than 128/160 respectively) Signed-off-by:
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David S. Miller authored
Sunil Goutham says: ==================== octeontx2: Flow control support and other misc changes This patch series adds flow control support (802.3 pause frames) and has other changes wrt generic admin function (AF) driver functionality. ==================== Signed-off-by: -
Sunil Goutham authored
Currently on the first check if the operation is still not finished, the poll goes to sleep for 2-5 usecs. But if for some reason (due to other priority stuff like interrupts etc) by the time the poll wakes up the 10ms time is expired then we don't check if operation is finished or not and return failure. This patch modifies poll logic to check HW operation after sleep so that the status is checked atleast twice. Signed-off-by:
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Sunil Goutham authored
Bus mastering is enabled by firmware, but when this driver is unbinded bus mastering gets disabled by the PCI subsystem which results interrupts not working when driver is reloaded. Hence set bus mastering everytime in probe(). Also - Converted pci_set_dma_mask() and pci_set_consistent_dma_mask() to dma_set_mask_and_coherent(). - Cleared transaction pending bit which gets set during driver unbind due to clearing of bus mastering (ME bit). Signed-off-by:
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Sunil Goutham authored
Currently there is no way for AF dependent drivers in any domain to check if the AF driver is loaded. This patch sets an ID for RVUM block which will automatically reflects in PF/VFs discovery register which they can check and defer their probe until AF is up. Signed-off-by:
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Linu Cherian authored
For retrieving info like interface MAC addresses, packet parser key extraction config etc currently a command is sent to firmware and firmware which periodically polls for commands, processes these and returns the info. This is resulting in interface initialization taking lot of time. To optimize this a memory region is shared between firmware and this driver, firmware while booting puts static info like these into that region for driver to read directly without using commands. With this - Logic for retrieving packet parser extraction config via commands is removed and repalced with using the shared 'fwdata' structure. - Now RVU MSIX vector address is also retrieved from this fwdata struct instead of from CSR. Otherwise when kexec/kdump crash kernel loads CSR will have a IOVA setup by primary kernel which impacts RVU PF/VF's interrupts. - Also added a mbox handler for PF/VF interfaces to retrieve their MAC addresses from AF. Signed-off-by:
Linu Cherian <lcherian@marvell.com> Signed-off-by:
Christina Jacob <cjacob@marvell.com> Signed-off-by:
Rakesh Babu <rsaladi2@marvell.com> Signed-off-by:
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Geetha sowjanya authored
Added mailbox requests to retrieve backpressure IDs from AF and Aura, CQ contexts are configured with these BPIDs. So that when resource levels reach configured thresholds they assert backpressure on the interface which is also mapped to same BPID. Also added support to enable/disable pause frames generation via ethtool. Signed-off-by:
Andrew Lunn <andrew@lunn.ch> Signed-off-by:
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Geetha sowjanya authored
CGX LMAC, the physical interface can generate pause frames when internal resources asserts backpressure due to exhaustion. This patch configures CGX to generate 802.3 pause frames. Also enabled processing of received pause frames on the line which will assert backpressure on the internal transmit path. Also added mailbox handlers for PF drivers to enable or disable pause frames anytime. Signed-off-by:
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Geetha sowjanya authored
Each of the interface receive channels can be backpressured by resources upon exhaustion or reaching configured threshold levels. Resources here are receive buffer queues (Auras) and pkt notification descriptor queues (CQs). Resources and interface channels are mapped using backpressure IDs (BPIDs). HW supports upto 512 BPIDs, this patch divides these BPIDs statically across CGX/LBK/SDP interfaces as follows. BPIDs 0 - 191 are mapped to LMAC channels, 16 per LMAC. BPIDs 192 - 255 are mapped to LBK channels. BPIDs 256 - 511 are mapped to SDP channels. Also did the needed basic configuration of BPIDs. Added mbox handlers with which a PF device can request for a BPID which it will use to configure Auras and CQs. Signed-off-by:
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Heiner Kallweit authored
Add constants for the used interrupts bits. This avoids the magic number for MII_VSC85XX_INT_MASK_MASK. Signed-off-by:
Heiner Kallweit <hkallweit1@gmail.com> Reviewed-by:
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- 01 Mar, 2020 5 commits
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Gustavo A. R. Silva authored
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: -
Gustavo A. R. Silva authored
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: -
Gustavo A. R. Silva authored
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: -
Gustavo A. R. Silva authored
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: -
Gustavo A. R. Silva authored
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by:
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