(add RAS/APEI folks) On Sat, 28 Aug 2021 at 13:31, Joe Perches <joe@xxxxxxxxxxx> wrote: > > On Sat, 2021-08-28 at 10:37 +0000, tip-bot2 for Rasmus Villemoes wrote: > > The following commit has been merged into the efi/core branch of tip: > [] > > efi: cper: fix scnprintf() use in cper_mem_err_location() > > > > The last two if-clauses fail to update n, so whatever they might have > > written at &msg[n] would be cut off by the final nul-termination. > > > > That nul-termination is redundant; scnprintf(), just like snprintf(), > > guarantees a nul-terminated output buffer, provided the buffer size is > > positive. > > > > And there's no need to discount one byte from the initial buffer; > > vsnprintf() expects to be given the full buffer size - it's not going > > to write the nul-terminator one beyond the given (buffer, size) pair. > [] > > diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c > [] > > @@ -221,7 +221,7 @@ static int cper_mem_err_location(struct cper_mem_err_compact *mem, char *msg) > > return 0; > > > > > > n = 0; > > - len = CPER_REC_LEN - 1; > > + len = CPER_REC_LEN; > > if (mem->validation_bits & CPER_MEM_VALID_NODE) > > n += scnprintf(msg + n, len - n, "node: %d ", mem->node); > > if (mem->validation_bits & CPER_MEM_VALID_CARD) > > [etc...] > > Is this always single threaded? > > It doesn't seem this is safe for reentry as the output buffer > being written into is a single static > > static char rcd_decode_str[CPER_REC_LEN]; > Good question. CPER error record decoding typically occurs in response to an error event raised by firmware, so I think this happens to work fine in practice. Whether this is guaranteed, I'm not so sure ...
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