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static bool next_command(Command **prev) { |
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if (*prev == NULL) { |
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*prev = (Command*) command_buf; |
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} else { |
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*prev = (Command*) (((char*) *prev) + (*prev)->size); |
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} |
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return *prev != ((Command*) (command_buf + command_buf_idx)); |
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} |
This function moves prev
size along which can and will cause unalignment and potential errors.
On ARM devices this causes a SIGBUS.
The people who helped me figure this out suggested this fix
static Command* push_command(int type, int size) {
+ size_t alignment = alignof(max_align_t) - 1;
+ size = (size + alignment) & ~alignment; // forward align to 4
Command *cmd = (Command*) (command_buf + command_buf_idx);
int n = command_buf_idx + size;
if (n > COMMAND_BUF_SIZE) {
fprintf(stderr, "Warning: (" __FILE__ "): exhausted command buffer\n");
return NULL;
}
command_buf_idx = n;
memset(cmd, 0, sizeof(Command));
cmd->type = type;
cmd->size = size;
return cmd;
}But alignof and max_align_t have been introduced with C11 so it might be of interest to replace the alignof with a static alignment of either 4 or 16 to be safe
lite/src/rencache.c
Lines 95 to 102 in 38bd9b3
This function moves prev size along which can and will cause unalignment and potential errors.
On ARM devices this causes a SIGBUS.
The people who helped me figure this out suggested this fix
static Command* push_command(int type, int size) { + size_t alignment = alignof(max_align_t) - 1; + size = (size + alignment) & ~alignment; // forward align to 4 Command *cmd = (Command*) (command_buf + command_buf_idx); int n = command_buf_idx + size; if (n > COMMAND_BUF_SIZE) { fprintf(stderr, "Warning: (" __FILE__ "): exhausted command buffer\n"); return NULL; } command_buf_idx = n; memset(cmd, 0, sizeof(Command)); cmd->type = type; cmd->size = size; return cmd; }But alignof and max_align_t have been introduced with C11 so it might be of interest to replace the alignof with a static alignment of either 4 or 16 to be safe