On Tue, Nov 12, 2024 at 10:09 AM John Garry <john.g.garry@xxxxxxxxxx> wrote: > > On 12/11/2024 17:42, Song Liu wrote: > > On Tue, Nov 12, 2024 at 8:10 AM John Garry<john.g.garry@xxxxxxxxxx> wrote: > >> For compiling with W=1, the following warning can be seen: > >> > >> drivers/md/raid5.c: In function ‘setup_conf’: > >> drivers/md/raid5.c:2423:12: error: ‘%s’ directive output may be truncated writing up to 31 bytes into a region of size between 16 and 26 [-Werror=format-truncation=] > >> "raid%d-%s", conf->level, mdname(conf->mddev)); > >> ^~ > >> drivers/md/raid5.c:2422:3: note: ‘snprintf’ output between 7 and 48 bytes into a destination of size 32 > > This is a bit confusing. Does this mean we actually need 48 bytes? > > I played with it myself, and 38 bytes is indeed enough to silent the > > warning. With 38 bytes, we have 4 bytes hole right behind > > cache_name, so I am thinking we should just use 40. > > > > WDYT? > > Indeed it is confusing... > So the string is "raid%d-%s", which is > 4B for "raid" > 10B for max int (right?) > 1B for '-' > 32B for DISK_NAME_LEN > 1B for NUL > > which totals 48 > > So I don't know why/how 38 is ok. Maybe there is some auto-padding going > on, like you hint at. > > Maybe just using 48 is better. Makes sense. I will update the patch to use 48, and apply it to md-6.13. Thanks, Song
