scripts/decode_stacktrace.sh: guess basepath if not specified

Guess path to kernel sources using known location of symbol "kernel_init".
Make basepath argument optional.

Before:

$ echo 'vfs_open+0x0/0x0' | ./scripts/decode_stacktrace.sh vmlinux ""
vfs_open (home/khlebnikov/src/linux/fs/open.c:912)

After:

$ echo 'vfs_open+0x0/0x0' | ./scripts/decode_stacktrace.sh vmlinux
vfs_open (fs/open.c:912)

Signed-off-by: Konstantin Khlebnikov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Sasha Levin <[email protected]>
Link: http://lkml.kernel.org/r/159282922803.248444.2379229451667913634.stgit@buzz
Signed-off-by: Linus Torvalds <[email protected]>
1 file changed