On Thu, 30 Jan 2025 15:58:49 +0100
David Marchand <david.march...@redhat.com> wrote:
> Registering a tracepoint handler was resulting so far in undefined
> behavior at runtime.
>
> The RTE_TRACE_POINT_REGISTER() macro was casting the tracepoint handler
> (which expects arguments) to a void (*)(void).
> At runtime, calling this handler while registering resulted in
> reading the current stack with no relation to this function prototype.
>
> Instead, declare an additional inline _register() handler for each
> tracepoint and make sure that the emitting macros in
> rte_trace_point_register.h only work on arguments name and type.
>
> The original tracepoint handler prototype is adjusted by adding a
> __rte_unused for each argument (since emitting macros do nothing
> with them).
> This last part introduces an implementation limit of 15 arguments.
>
> With this change in place, the workaround in dmadev tracepoints can be
> removed.
>
> Signed-off-by: David Marchand <david.march...@redhat.com>
When I build with -Db_santize=undefined the following warning shows up.
It seems related.
In function ‘rte_ethdev_trace_get_dcb_info’,
inlined from ‘rte_eth_dev_get_dcb_info’ at
../lib/ethdev/rte_ethdev.c:6720:2:
../lib/eal/include/rte_trace_point.h:381:9: warning: writing 1 byte into a
region of size 0 [-Wstringop-overflow=]
381 | memcpy(mem, &(in), sizeof(in)); \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../lib/eal/include/rte_trace_point.h:53:9: note: in definition of macro
‘__RTE_TRACE_POINT’
53 | __VA_ARGS__ \
| ^~~~~~~~~~~
../lib/ethdev/ethdev_trace.h:1213:1: note: in expansion of macro
‘RTE_TRACE_POINT’
1213 | RTE_TRACE_POINT(
| ^~~~~~~~~~~~~~~
../lib/eal/include/rte_trace_point.h:399:9: note: in expansion of macro
‘__rte_trace_point_emit’
399 | __rte_trace_point_emit(len, uint8_t); \
| ^~~~~~~~~~~~~~~~~~~~~~
../lib/ethdev/ethdev_trace.h:1223:9: note: in expansion of macro
‘rte_trace_point_emit_blob’
1223 | rte_trace_point_emit_blob(dcb_info->tc_bws, num_tcs);
| ^~~~~~~~~~~~~~~~~~~~~~~~~
In function ‘rte_eth_dev_get_dcb_info’:
cc1: note: destination object is likely at address zero
In function ‘rte_ethdev_trace_get_dcb_info’,
inlined from ‘rte_eth_dev_get_dcb_info’ at
../lib/ethdev/rte_ethdev.c:6720:2:
../lib/eal/include/rte_trace_point.h:401:9: warning: ‘memset’ offset [0, 55] is
out of the bounds [0, 0] [-Warray-bounds=]
401 | memset(RTE_PTR_ADD(mem, len), 0, RTE_TRACE_BLOB_LEN_MAX - len);
\
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../lib/eal/include/rte_trace_point.h:53:9: note: in definition of macro
‘__RTE_TRACE_POINT’
53 | __VA_ARGS__ \
| ^~~~~~~~~~~
../lib/ethdev/ethdev_trace.h:1213:1: note: in expansion of macro
‘RTE_TRACE_POINT’
1213 | RTE_TRACE_POINT(
| ^~~~~~~~~~~~~~~
../lib/ethdev/ethdev_trace.h:1222:9: note: in expansion of macro
‘rte_trace_point_emit_blob’
1222 | rte_trace_point_emit_blob(dcb_info->prio_tc,
num_user_priorities);
