On 1/15/20 11:53 PM, Michael Ellerman wrote: > Michael Bringmann <m...@linux.ibm.com> writes: >> Correct overflow problem in calculation+display of Maximum Memory >> value to syscfg where 32bits is insufficient. >> >> Signed-off-by: Michael Bringmann <m...@linux.ibm.com> >> --- >> arch/powerpc/platforms/pseries/lparcfg.c | 8 ++++---- >> 1 file changed, 4 insertions(+), 4 deletions(-) >> >> diff --git a/arch/powerpc/platforms/pseries/lparcfg.c >> b/arch/powerpc/platforms/pseries/lparcfg.c >> index e33e8bc..f00411c 100644 >> --- a/arch/powerpc/platforms/pseries/lparcfg.c >> +++ b/arch/powerpc/platforms/pseries/lparcfg.c >> @@ -433,12 +433,12 @@ static void parse_em_data(struct seq_file *m) >> >> static void maxmem_data(struct seq_file *m) >> { >> - unsigned long maxmem = 0; >> + u64 maxmem = 0; > > This is 64-bit only code, so u64 == unsigned long. > >> - maxmem += drmem_info->n_lmbs * drmem_info->lmb_size; >> - maxmem += hugetlb_total_pages() * PAGE_SIZE; >> + maxmem += (u64)drmem_info->n_lmbs * drmem_info->lmb_size; > > The only problem AFAICS is n_lmbs is int and lmb_size is u32, so this > multiplication will overflow. > >> + maxmem += (u64)hugetlb_total_pages() * PAGE_SIZE; > > hugetlb_total_pages() already returns unsigned long. > >> - seq_printf(m, "MaxMem=%ld\n", maxmem); >> + seq_printf(m, "MaxMem=%llu\n", maxmem); >> } > > This should be sufficient? > > diff --git a/arch/powerpc/platforms/pseries/lparcfg.c > b/arch/powerpc/platforms/pseries/lparcfg.c > index e33e8bc4b69b..38c306551f76 100644 > --- a/arch/powerpc/platforms/pseries/lparcfg.c > +++ b/arch/powerpc/platforms/pseries/lparcfg.c > @@ -435,10 +435,10 @@ static void maxmem_data(struct seq_file *m) > { > unsigned long maxmem = 0; > > - maxmem += drmem_info->n_lmbs * drmem_info->lmb_size; > + maxmem += (unsigned long)drmem_info->n_lmbs * drmem_info->lmb_size; > maxmem += hugetlb_total_pages() * PAGE_SIZE; > > - seq_printf(m, "MaxMem=%ld\n", maxmem); > + seq_printf(m, "MaxMem=%lu\n", maxmem); > } > > static int pseries_lparcfg_data(struct seq_file *m, void *v) > > > cheers >
Trying it out. -- Michael W. Bringmann Linux Technology Center IBM Corporation Tie-Line 363-5196 External: (512) 286-5196 Cell: (512) 466-0650 m...@linux.ibm.com