Created attachment 230361 [details] Image triggering btrfsck to segv The fuzzer hit again: ==32522==ERROR: AddressSanitizer: SEGV on unknown address 0x00027fff801c (pc 0x0000004a952e bp 0x7fff5222ce70 sp 0x7fff5222c600 T0) #0 0x4a952d in __asan_memcpy (/home/lukas/dev/btrfsfuzz/bin-asan/bin/btrfs+0x4a952d) #1 0x66a323 in read_extent_buffer /home/lukas/dev/btrfsfuzz/src-asan/extent_io.c:867:2 #2 0x55ad25 in btrfs_node_key /home/lukas/dev/btrfsfuzz/src-asan/./ctree.h:1668:2 #3 0x58573b in check_fs_root /home/lukas/dev/btrfsfuzz/src-asan/cmds-check.c:3748:3 #4 0x544136 in check_fs_roots /home/lukas/dev/btrfsfuzz/src-asan/cmds-check.c:3896:10 #5 0x53d8c5 in cmd_check /home/lukas/dev/btrfsfuzz/src-asan/cmds-check.c:11470:8 #6 0x4f105f in main /home/lukas/dev/btrfsfuzz/src-asan/btrfs.c:243:8 #7 0x7fea1bcb7730 in __libc_start_main (/lib64/libc.so.6+0x20730) #8 0x421238 in _start (/home/lukas/dev/btrfsfuzz/bin-asan/bin/btrfs+0x421238) See the attached image to reproduce using btrfs-progs btrfs-progs v4.7-42-g56e9586.
Created attachment 230371 [details] Full ASAN-Log
Root fix for btrfsck: https://patchwork.kernel.org/patch/9304945/ Along with early warning patch, could just ignore such unaligend extent bytenr https://patchwork.kernel.org/patch/9304947/
Fixes and image are in git, will be part of the next release. Closing, thanks.