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fd69b2f7d5
The recent changes to get_unaligned() resulted in a new sparse warning: net/rds/ib_cm.c:96:35: sparse: sparse: incorrect type in argument 1 (different modifiers) @@ expected void * @@ got restricted __be64 const * @@ net/rds/ib_cm.c:96:35: sparse: expected void * net/rds/ib_cm.c:96:35: sparse: got restricted __be64 const * The updated get_unaligned_t() uses __unqual_scalar_typeof() to get an unqualified type. This works correctly for the compilers, but fails for sparse when the data type is __be64 (or any other __beNN variant). On sparse runs (C=[12]) __beNN types are annotated with __attribute__((bitwise)). That annotation allows sparse to detect incompatible operations on __beNN variables, but it also prevents sparse from evaluating the _Generic() in __unqual_scalar_typeof() and map __beNN to a unqualified scalar type, so it ends up with the default, i.e. the original qualified type of a 'const __beNN' pointer. That then ends up as the first pointer argument to builtin_memcpy(), which obviously causes the above sparse warnings. The sparse git tree supports typeof_unqual() now, which allows to use it instead of the _Generic() based __unqual_scalar_typeof(). With that sparse correctly evaluates the unqualified type and keeps the __beNN logic intact. The downside is that this requires a top of tree sparse build and an old sparse version will emit a metric ton of incomprehensible error messages before it dies with a segfault. Therefore implement a sanity check which validates that the checker is available and capable of handling typeof_unqual(). Emit a warning if not so the user can take informed action. [ tglx: Move the evaluation of USE_TYPEOF_UNQUAL to compiler_types.h so it is set before use and implement the sanity checker ] Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Acked-by: Ian Rogers <irogers@google.com> Link: https://patch.msgid.link/87ecnp2zh3.ffs@tglx Closes: https://lore.kernel.org/oe-kbuild-all/202601150001.sKSN644a-lkp@intel.com/
20 lines
419 B
Bash
Executable File
20 lines
419 B
Bash
Executable File
#!/bin/sh -eu
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# SPDX-License-Identifier: GPL-2.0
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[ ! -x "$(command -v "$1")" ] && exit 1
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tmp_file=$(mktemp)
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trap "rm -f $tmp_file" EXIT
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cat << EOF >$tmp_file
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static inline int u(const int *q)
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{
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__typeof_unqual__(*q) v = *q;
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return v;
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}
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EOF
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# sparse happily exits with 0 on error so validate
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# there is none on stderr. Use awk as grep is a pain with sh -e
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$@ $tmp_file 2>&1 | awk -v c=1 '/error/{c=0}END{print c}'
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