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Diffstat (limited to 'Documentation/s390/s390dbf.txt')
| -rw-r--r-- | Documentation/s390/s390dbf.txt | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/s390/s390dbf.txt b/Documentation/s390/s390dbf.txt index 2d10053dd97e..ae66f9b90a25 100644 --- a/Documentation/s390/s390dbf.txt +++ b/Documentation/s390/s390dbf.txt | |||
| @@ -495,6 +495,13 @@ and for each vararg a long value. So e.g. for a debug entry with a format | |||
| 495 | string plus two varargs one would need to allocate a (3 * sizeof(long)) | 495 | string plus two varargs one would need to allocate a (3 * sizeof(long)) |
| 496 | byte data area in the debug_register() function. | 496 | byte data area in the debug_register() function. |
| 497 | 497 | ||
| 498 | IMPORTANT: Using "%s" in sprintf event functions is dangerous. You can only | ||
| 499 | use "%s" in the sprintf event functions, if the memory for the passed string is | ||
| 500 | available as long as the debug feature exists. The reason behind this is that | ||
| 501 | due to performance considerations only a pointer to the string is stored in | ||
| 502 | the debug feature. If you log a string that is freed afterwards, you will get | ||
| 503 | an OOPS when inspecting the debug feature, because then the debug feature will | ||
| 504 | access the already freed memory. | ||
| 498 | 505 | ||
| 499 | NOTE: If using the sprintf view do NOT use other event/exception functions | 506 | NOTE: If using the sprintf view do NOT use other event/exception functions |
| 500 | than the sprintf-event and -exception functions. | 507 | than the sprintf-event and -exception functions. |