On Wed, Oct 27, 2021 at 09:09:24PM +1100, Stephen Rothwell wrote: > Hi all, > > [I am not sure why this error only popped up after I merged Andrew's > patch set ...] > > After merging the btrfs tree, today's linux-next build (x86_64 > allmodconfig) failed like this: > > In file included from include/linux/string.h:253, > from include/linux/bitmap.h:11, > from include/linux/cpumask.h:12, > from arch/x86/include/asm/cpumask.h:5, > from arch/x86/include/asm/msr.h:11, > from arch/x86/include/asm/processor.h:22, > from arch/x86/include/asm/cpufeature.h:5, > from arch/x86/include/asm/thread_info.h:53, > from include/linux/thread_info.h:60, > from arch/x86/include/asm/preempt.h:7, > from include/linux/preempt.h:78, > from include/linux/spinlock.h:55, > from include/linux/wait.h:9, > from include/linux/mempool.h:8, > from include/linux/bio.h:8, > from fs/btrfs/ioctl.c:7: > In function 'memcpy', > inlined from '_btrfs_ioctl_send' at fs/btrfs/ioctl.c:4846:3: > include/linux/fortify-string.h:219:4: error: call to '__write_overflow' declared with attribute error: detected write beyond size of object (1st parameter) > 219 | __write_overflow(); > | ^~~~~~~~~~~~~~~~~~ > > Caused by commit > > c8d9cdfc766d ("btrfs: send: prepare for v2 protocol") > > This changes the "reserved" field of struct btrfs_ioctl_send_args from 4 u64's to 3, but the above memcpy is copying the "reserved" filed from a struct btrfs_ioctl_send_args_32 (4 u64s) into it. I'll fix it in the next update. There are two structures for the ioctl that need to be in sync but I forgot to do that.