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From: "ppluzhnikov at google dot com" <sourceware-bugzilla@sourceware.org>
To: gdb-prs@sourceware.org
Subject: [Bug breakpoints/16297] New: catch syscall read (syscall 0) doesn't
 work on Linux/x86_64
Date: Fri, 06 Dec 2013 06:40:00 -0000
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https://sourceware.org/bugzilla/show_bug.cgi?id=16297

            Bug ID: 16297
           Summary: catch syscall read (syscall 0) doesn't work on
                    Linux/x86_64
           Product: gdb
           Version: HEAD
            Status: NEW
          Severity: normal
          Priority: P2
         Component: breakpoints
          Assignee: unassigned at sourceware dot org
          Reporter: ppluzhnikov at google dot com

Using current trunk:
GNU gdb (GDB) 7.6.50.20131206-cvs

strace -e trace=read /bin/date
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\340!\0\0\0\0\0\0"...,
832) = 832
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\200\30\2\0\0\0\0\0"...,
832) = 832
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\200l\0\0\0\0\0\0"...,
832) = 832
read(3, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\4\0\0\0\4\0\0\0\0"..., 4096)
= 2819
read(3, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\5\0\0\0\5\0\0\0\0"..., 4096)
= 1802
Thu Dec  5 22:29:53 PST 2013

Clearly read is being invoked to load shared libraries, and to read
/usr/lib/locale/locale-archive

gdb /bin/date
GNU gdb (GDB) 7.6.50.20131206-cvs
Copyright (C) 2013 Free Software Foundation, Inc.
...
Reading symbols from /bin/date...(no debugging symbols found)...done.
(gdb) catch syscall read
Catchpoint 1 (syscall 'read' [0])
(gdb) run
Starting program: /bin/date
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Thu Dec  5 22:34:48 PST 2013
[Inferior 1 (process 10313) exited normally]
(gdb) quit


No problem with write (syscall 1).
Might this have something to do with _NR_read being 0 on Linux/x86_64?

Same problem reported for gdb Ubuntu/Linaro 7.4-2012.04-0ubuntu2.1,
so this is likely not new.

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