On Wed, Oct 06, 2021 at 06:54:07PM +0200, Carlos Maiolino wrote: > > > My biggest motivation was actually seeing xfs_io crashing due a sigbus > > > while running generic/172 and generic/173. And personally, I'd rather see an > > > error message like "attempt to mmap/mwrite beyond EOF" than seeing it crash. > > > Also, as you mentioned, programs are allowed to set up such kind of > > > configuration (IIUC what you mean, mixing mmap, extend, truncate, etc), so, I > > > believe such userspace programs should also ensure they are not attempting to > > > write to invalid memory. > > > > This patch would /also/ prevent us from writing an fstest to check that > > a process /does/ get SIGBUS when writing to a mapping beyond EOF. Huh, > > we don't have a test for that... After looking closer into g/173, I see what you mean now. > > The whole command that ends up receiving a SIGBUS is: > > xfs_io -i -f -c 'mmap -rw 0 41943040' -c 'mwrite -S 0x62 0 41943040' And... > At a later point, I just did some tests using an empty, 0 > sized file. And playing around with a 0 sized file without coming back to look closer into g/173 was what had been blinding me. Please just disregard this patch and my apologies for the noise. -- Carlos
