I'm ready to swear on a stack of Knuth volumes that gdb has lost its mind.
But, I'm willing to consider the remote possibility that I don't know how
to use gdb ;) (Because I really don't.)
This is my annotated copy/paste from a single gdb session:
#gdb /bin/mount
GNU gdb (Gentoo 7.9 vanilla) 7.9
<GNU boilerplate snipped>
(gdb) start
Temporary breakpoint 1 at 0x403000: file
/var/tmp/portage/sys-apps/util-linux-2.26.1-r1/work/util-linux-2.26.1/sys-utils/mount.c,
line 789.
Starting program: /bin/mount
Temporary breakpoint 1, main (argc=1, argv=0x7ffc3508e108)
at
/var/tmp/portage/sys-apps/util-linux-2.26.1-r1/work/util-linux-2.26.1/sys-utils/mount.c:789
789 {
(gdb) list mount.c:1020
<I picked line 1020 because I know from previous gdb sessions that it
calls the print_all function, which is the one I really want to debug>
1015 !mnt_context_get_target(cxt) &&
1016 !argc &&
1017 !all) {
1018 if (oper || mnt_context_get_options(cxt))
1019 usage(stderr);
1020 print_all(cxt, types, show_labels);
1021 goto done;
1022 }
1023
1024 /* Non-root users are allowed to use -t to print_all(),
<I want to debug the function named print_all, so I set a breakpoint there>
(gdb) break print_all
Breakpoint 2 at 0x4037fd: file
/var/tmp/portage/sys-apps/util-linux-2.26.1-r1/work/util-linux-2.26.1/sys-utils/mount.c,
line 130.
<Okay, this is where gdb does something crazy. Note that (see the line above)
gdb set the breakpoint at mount.c:130, but in fact print_all is defined at
mount.c:123, seven lines earlier>
(gdb) list mount.c:123
118 else
119 fputc(*p, stdout);
120 }
121 }
122
123 static void print_all(struct libmnt_context *cxt, char *pattern, int
show_label)
124 {
125 struct libmnt_table *tb;
126 struct libmnt_iter *itr = NULL;
127 struct libmnt_fs *fs;
(gdb)
This seems to me to be very buggy behavior, but I'd like to get opinions from
people who really know gdb, which I don't.
And thanks for reading this far :)
