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authorMike Frysinger <vapier@gentoo.org>2015-09-20 03:40:16 -0400
committerMike Frysinger <vapier@gentoo.org>2015-09-20 03:40:16 -0400
commitc17c4b85ca9e9af75bc16c9e49b6bf0b3ee6b4c8 (patch)
tree400953685e512a2e7f7c74c4bcc034b0169d50c0 /libsandbox
parentlibsandbox: improve debugging output a bit (diff)
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libsandbox: work around process_vm_readv EFAULTsv2.8
Some people are seeing this call fail, but it's not clear why. Include more debugging output so as to improve the reports, and let the code fall back to the existing ptrace logic since that seems to work. This will at least unblock people's builds. URL: https://bugs.gentoo.org/560396 Reported-by: Jeroen Roovers <jer@gentoo.org> Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Diffstat (limited to 'libsandbox')
-rw-r--r--libsandbox/trace.c17
1 files changed, 15 insertions, 2 deletions
diff --git a/libsandbox/trace.c b/libsandbox/trace.c
index 1d40392..ed05c4d 100644
--- a/libsandbox/trace.c
+++ b/libsandbox/trace.c
@@ -104,10 +104,23 @@ static char *do_peekstr(unsigned long lptr)
while (1) {
if (process_vm_readv(trace_pid, &liov, 1, &riov, 1, 0) == -1) {
- if (errno == ENOSYS)
+ int e = errno;
+ if (e == ENOSYS)
break;
+ sb_eqawarn("process_vm_readv(%i, %p{%p, %zu}, 1, %p{%p, %zu}, 1, 0) failed: %s\n",
+ trace_pid,
+ &liov, liov.iov_base, liov.iov_len,
+ &riov, riov.iov_base, riov.iov_len,
+ strerror(e));
+ if (e == EFAULT) {
+ /* This sometimes happens, but it's not clear why.
+ * Throw some extended debugging info before falling
+ * back to the ptrace code. #560396
+ */
+ break;
+ }
sb_ebort("ISE:do_peekstr: process_vm_readv() hates us: %s\n",
- strerror(errno));
+ strerror(e));
}
for (i = 0; i < liov.iov_len; ++i)