In the Linux kernel, the following vulnerability has been resolved: btrfs: output extra debug info if we failed to find an inline backref [BUG] Syzbot reported several warning triggered inside lookupinlineextentbackref(). [CAUSE] As usual, the reproducer doesn't reliably trigger locally here, but at least we know the WARNON() is triggered when an inline backref can not be found, and it can only be triggered when @insert is true. (I.e. inserting a new inline backref, which means the backref should already exist) [ENHANCEMENT] After the WARN_ON(), dump all the parameters and the extent tree leaf to help debug.