Looking at some cores in eu-stack, I found that they were not being
backtraced.
This was because elfutils had not found some modules (e.g. libc-2.22.so)
in report_r_debug.
That is because it has a limit on the number of link map entries it will
look at, to avoid loops in corrupted core files.
The example I found had:
- 36 elements
- 109 iterations
I have increased the limit, and this seems to solve the problem.
Florian Weimer suggested that the problem is caused by use of
`-z separate-code' although I have not yet managed to confirm this.
See also:
https://sourceware.org/pipermail/elfutils-devel/2023q2/006149.html
Signed-off-by: Luke Diamand <ldiam...@roku.com>
---
libdwfl/link_map.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/libdwfl/link_map.c b/libdwfl/link_map.c
index 06d85eb6..975910a9 100644
--- a/libdwfl/link_map.c
+++ b/libdwfl/link_map.c
@@ -330,12 +330,13 @@ report_r_debug (uint_fast8_t elfclass, uint_fast8_t
elfdata,
Dwfl_Module **lastmodp = &dwfl->modulelist;
int result = 0;
- /* There can't be more elements in the link_map list than there are
- segments. DWFL->lookup_elts is probably twice that number, so it
- is certainly above the upper bound. If we iterate too many times,
- there must be a loop in the pointers due to link_map clobberation. */
+ /* Keep an upper bound on the number of iterations - if we iterate
+ * too many times, there must be a loop in the pointers due to link_map
+ * clobberation.
+ */
size_t iterations = 0;
- while (next != 0 && ++iterations < dwfl->lookup_elts)
+
+ while (next != 0 && ++iterations < dwfl->lookup_elts * 5)
{
if (read_addrs (&memory_closure, elfclass, elfdata,
&buffer, &buffer_available, next, &read_vaddr,
--
2.39.1
