Jeff Johnson [off-list ref] writes:

On 7/16/2024 4:06 AM, Paolo Abeni wrote:

quoted

gcc 11.4.1-3 warns about memcpy() with overlapping pointers:

drivers/net/wireless/ath/ath12k/wow.c: In function
‘ath12k_wow_convert_8023_to_80211.constprop’:
./include/linux/fortify-string.h:114:33: error: ‘__builtin_memcpy’
accessing 18446744073709551611 or more bytes at offsets 0 and 0
overlaps 9223372036854775799 bytes at offset -9223372036854775804
[-Werror=restrict]
  114 | #define __underlying_memcpy     __builtin_memcpy
      |                                 ^
./include/linux/fortify-string.h:637:9: note: in expansion of macro
‘__underlying_memcpy’
  637 |         __underlying_##op(p, q, __fortify_size);                        \
      |         ^~~~~~~~~~~~~
./include/linux/fortify-string.h:682:26: note: in expansion of macro
‘__fortify_memcpy_chk’
  682 | #define memcpy(p, q, s)  __fortify_memcpy_chk(p, q, s,                  \
      |                          ^~~~~~~~~~~~~~~~~~~~
drivers/net/wireless/ath/ath12k/wow.c:190:25: note: in expansion of macro ‘memcpy’
  190 |                         memcpy(pat, eth_pat, eth_pat_len);
      |                         ^~~~~~
./include/linux/fortify-string.h:114:33: error: ‘__builtin_memcpy’
accessing 18446744073709551605 or more bytes at offsets 0 and 0
overlaps 9223372036854775787 bytes at offset -9223372036854775798
[-Werror=restrict]
  114 | #define __underlying_memcpy     __builtin_memcpy
      |                                 ^
./include/linux/fortify-string.h:637:9: note: in expansion of macro
‘__underlying_memcpy’
  637 |         __underlying_##op(p, q, __fortify_size);                        \
      |         ^~~~~~~~~~~~~
./include/linux/fortify-string.h:682:26: note: in expansion of macro
‘__fortify_memcpy_chk’
  682 | #define memcpy(p, q, s)  __fortify_memcpy_chk(p, q, s,                  \
      |                          ^~~~~~~~~~~~~~~~~~~~
drivers/net/wireless/ath/ath12k/wow.c:232:25: note: in expansion of macro ‘memcpy’
  232 |                         memcpy(pat, eth_pat, eth_pat_len);
      |                         ^~~~~~

The sum of size_t operands can overflow SIZE_MAX, triggering the
warning.
Address the issue using the suitable helper.

Fixes: 4a3c212eee0e ("wifi: ath12k: add basic WoW functionalities")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
Only built tested. Sending directly to net to reduce the RTT, but no
objections to go through the WiFi tree first

Since Kalle is on holiday please go ahead and take this via net.
This looks nicer than Kalle's version :)

Indeed, this is nicer. Thanks Paolo!

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