It looks like you're using a pointer that has been freed some time earlier.
On Sun, Jun 7, 2020, 10:52 James Read <jamesread5...@gmail.com> wrote: > I'm getting a series of Invalid read of size 1 errors. These seem to be > related to strlen() calls. How is it possible for strlen() to make an > invalid read? > > Here is my valgrind output: > > ==21737== Invalid read of size 1 > ==21737== at 0x483EF46: strlen (in > /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so) > ==21737== by 0x10D7E6: crawler_init (crawler.c:1165) > ==21737== by 0x10E417: main (crawler.c:1383) > ==21737== Address 0x7adf2c0 is 0 bytes inside a block of size 52 free'd > ==21737== at 0x483CA3F: free (in > /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so) > ==21737== by 0x10CC43: new_head_conn (crawler.c:911) > ==21737== by 0x10D751: crawler_init (crawler.c:1148) > ==21737== by 0x10E417: main (crawler.c:1383) > ==21737== Block was alloc'd at > ==21737== at 0x483B7F3: malloc (in > /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so) > ==21737== by 0x50DD50E: strdup (strdup.c:42) > ==21737== by 0x10D70C: crawler_init (crawler.c:1145) > ==21737== by 0x10E417: main (crawler.c:1383) > ==21737== > ==21737== Invalid read of size 1 > ==21737== at 0x483EF54: strlen (in > /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so) > ==21737== by 0x10D7E6: crawler_init (crawler.c:1165) > ==21737== by 0x10E417: main (crawler.c:1383) > ==21737== Address 0x7adf2c1 is 1 bytes inside a block of size 52 free'd > ==21737== at 0x483CA3F: free (in > /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so) > ==21737== by 0x10CC43: new_head_conn (crawler.c:911) > ==21737== by 0x10D751: crawler_init (crawler.c:1148) > ==21737== by 0x10E417: main (crawler.c:1383) > ==21737== Block was alloc'd at > ==21737== at 0x483B7F3: malloc (in > /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so) > ==21737== by 0x50DD50E: strdup (strdup.c:42) > ==21737== by 0x10D70C: crawler_init (crawler.c:1145) > ==21737== by 0x10E417: main (crawler.c:1383) > ==21737== > ==21737== Invalid read of size 1 > ==21737== at 0x483EF46: strlen (in > /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so) > ==21737== by 0x10D89B: crawler_init (crawler.c:1166) > ==21737== by 0x10E417: main (crawler.c:1383) > ==21737== Address 0x7adf2c0 is 0 bytes inside a block of size 52 free'd > ==21737== at 0x483CA3F: free (in > /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so) > ==21737== by 0x10CC43: new_head_conn (crawler.c:911) > ==21737== by 0x10D751: crawler_init (crawler.c:1148) > ==21737== by 0x10E417: main (crawler.c:1383) > ==21737== Block was alloc'd at > ==21737== at 0x483B7F3: malloc (in > /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so) > ==21737== by 0x50DD50E: strdup (strdup.c:42) > ==21737== by 0x10D70C: crawler_init (crawler.c:1145) > ==21737== by 0x10E417: main (crawler.c:1383) > ==21737== > ==21737== Invalid read of size 1 > ==21737== at 0x483EF54: strlen (in > /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so) > ==21737== by 0x10D89B: crawler_init (crawler.c:1166) > ==21737== by 0x10E417: main (crawler.c:1383) > ==21737== Address 0x7adf2c1 is 1 bytes inside a block of size 52 free'd > ==21737== at 0x483CA3F: free (in > /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so) > ==21737== by 0x10CC43: new_head_conn (crawler.c:911) > ==21737== by 0x10D751: crawler_init (crawler.c:1148) > ==21737== by 0x10E417: main (crawler.c:1383) > ==21737== Block was alloc'd at > ==21737== at 0x483B7F3: malloc (in > /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so) > ==21737== by 0x50DD50E: strdup (strdup.c:42) > ==21737== by 0x10D70C: crawler_init (crawler.c:1145) > ==21737== by 0x10E417: main (crawler.c:1383) > ==21737== > ==21737== Invalid read of size 1 > ==21737== at 0x4993BFD: ??? (in > /usr/lib/x86_64-linux-gnu/libmysqlclient.so.21.1.20) > ==21737== by 0x49D0D82: ??? (in > /usr/lib/x86_64-linux-gnu/libmysqlclient.so.21.1.20) > ==21737== by 0x49759AF: mysql_real_escape_string_quote (in > /usr/lib/x86_64-linux-gnu/libmysqlclient.so.21.1.20) > ==21737== by 0x49759DB: mysql_real_escape_string (in > /usr/lib/x86_64-linux-gnu/libmysqlclient.so.21.1.20) > ==21737== by 0x10D8BB: crawler_init (crawler.c:1166) > ==21737== by 0x10E417: main (crawler.c:1383) > ==21737== Address 0x7adf2c0 is 0 bytes inside a block of size 52 free'd > ==21737== at 0x483CA3F: free (in > /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so) > ==21737== by 0x10CC43: new_head_conn (crawler.c:911) > ==21737== by 0x10D751: crawler_init (crawler.c:1148) > ==21737== by 0x10E417: main (crawler.c:1383) > ==21737== Block was alloc'd at > ==21737== at 0x483B7F3: malloc (in > /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so) > ==21737== by 0x50DD50E: strdup (strdup.c:42) > ==21737== by 0x10D70C: crawler_init (crawler.c:1145) > ==21737== by 0x10E417: main (crawler.c:1383) > ==21737== > ==21737== Invalid read of size 1 > ==21737== at 0x499D751: ??? (in > /usr/lib/x86_64-linux-gnu/libmysqlclient.so.21.1.20) > ==21737== by 0x49D0D98: ??? (in > /usr/lib/x86_64-linux-gnu/libmysqlclient.so.21.1.20) > ==21737== by 0x49759AF: mysql_real_escape_string_quote (in > /usr/lib/x86_64-linux-gnu/libmysqlclient.so.21.1.20) > ==21737== by 0x49759DB: mysql_real_escape_string (in > /usr/lib/x86_64-linux-gnu/libmysqlclient.so.21.1.20) > ==21737== by 0x10D8BB: crawler_init (crawler.c:1166) > ==21737== by 0x10E417: main (crawler.c:1383) > ==21737== Address 0x7adf2c0 is 0 bytes inside a block of size 52 free'd > ==21737== at 0x483CA3F: free (in > /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so) > ==21737== by 0x10CC43: new_head_conn (crawler.c:911) > ==21737== by 0x10D751: crawler_init (crawler.c:1148) > ==21737== by 0x10E417: main (crawler.c:1383) > ==21737== Block was alloc'd at > ==21737== at 0x483B7F3: malloc (in > /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so) > ==21737== by 0x50DD50E: strdup (strdup.c:42) > ==21737== by 0x10D70C: crawler_init (crawler.c:1145) > ==21737== by 0x10E417: main (crawler.c:1383) > ==21737== > ==21737== Invalid read of size 1 > ==21737== at 0x49D0DCB: ??? (in > /usr/lib/x86_64-linux-gnu/libmysqlclient.so.21.1.20) > ==21737== by 0x49759AF: mysql_real_escape_string_quote (in > /usr/lib/x86_64-linux-gnu/libmysqlclient.so.21.1.20) > ==21737== by 0x49759DB: mysql_real_escape_string (in > /usr/lib/x86_64-linux-gnu/libmysqlclient.so.21.1.20) > ==21737== by 0x10D8BB: crawler_init (crawler.c:1166) > ==21737== by 0x10E417: main (crawler.c:1383) > ==21737== Address 0x7adf2c0 is 0 bytes inside a block of size 52 free'd > ==21737== at 0x483CA3F: free (in > /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so) > ==21737== by 0x10CC43: new_head_conn (crawler.c:911) > ==21737== by 0x10D751: crawler_init (crawler.c:1148) > ==21737== by 0x10E417: main (crawler.c:1383) > ==21737== Block was alloc'd at > ==21737== at 0x483B7F3: malloc (in > /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so) > ==21737== by 0x50DD50E: strdup (strdup.c:42) > ==21737== by 0x10D70C: crawler_init (crawler.c:1145) > ==21737== by 0x10E417: main (crawler.c:1383) > ==21737== > > Source code for my app is available at > https://github.com/JamesRead5737/webcrawler > > Thanks, > James Read > _______________________________________________ > Valgrind-users mailing list > Valgrind-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/valgrind-users >
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