On Fri, Jun 26, 2026 at 08:47:50PM +0200, Thorsten Blum wrote: > Now that struct rtas_error_log uses a flexible array member for the > extended log buffer, use struct_size() to calculate the total RTAS error > log size and avoid using the hard-coded header size of 8 bytes. > > Use memcpy_and_pad() instead of memset() and memcpy() while at it. > > Signed-off-by: Thorsten Blum <[email protected]> > --- > arch/powerpc/platforms/pseries/ras.c | 17 +++++++---------- > 1 file changed, 7 insertions(+), 10 deletions(-) > > diff --git a/arch/powerpc/platforms/pseries/ras.c > b/arch/powerpc/platforms/pseries/ras.c > index adafd593d9d3..d54030fd2324 100644 > --- a/arch/powerpc/platforms/pseries/ras.c > +++ b/arch/powerpc/platforms/pseries/ras.c > @@ -7,6 +7,7 @@ > #include <linux/interrupt.h> > #include <linux/irq.h> > #include <linux/of.h> > +#include <linux/overflow.h> > #include <linux/fs.h> > #include <linux/reboot.h> > #include <linux/irq_work.h> > @@ -440,6 +441,8 @@ static __be64 *fwnmi_get_savep(struct pt_regs *regs) > static struct rtas_error_log *fwnmi_get_errinfo(struct pt_regs *regs) > { > struct rtas_error_log *h; > + u32 extended_log_length; > + size_t len; > __be64 *savep; > > savep = fwnmi_get_savep(regs); > @@ -449,17 +452,11 @@ static struct rtas_error_log *fwnmi_get_errinfo(struct > pt_regs *regs) > regs->gpr[3] = be64_to_cpu(savep[0]); /* restore original r3 */ > > h = (struct rtas_error_log *)&savep[1]; > + extended_log_length = rtas_error_extended(h) ? > rtas_error_extended_log_length(h) : 0; > + len = struct_size(h, buffer, extended_log_length); > + len = min(len, RTAS_ERROR_LOG_MAX); > /* Use the per cpu buffer from paca to store rtas error log */ > - memset(local_paca->mce_data_buf, 0, RTAS_ERROR_LOG_MAX); > - if (!rtas_error_extended(h)) { > - memcpy(local_paca->mce_data_buf, h, sizeof(__u64)); > - } else { > - int len, error_log_length; > - > - error_log_length = 8 + rtas_error_extended_log_length(h); > - len = min_t(int, error_log_length, RTAS_ERROR_LOG_MAX); > - memcpy(local_paca->mce_data_buf, h, len); > - } > + memcpy_and_pad(local_paca->mce_data_buf, RTAS_ERROR_LOG_MAX, h, len, 0);
Sashiko found that memcpy_and_pad() isn't safe here because fwnmi_get_errinfo() is part of a real-mode path: https://sashiko.dev/#/patchset/20260626184750.166642-3-thorsten.blum%40linux.dev I'll send a v2 and keep memset() and memcpy() separate.
