From: Jun Sun <jsun@mvista.com>
To: linux-mips <linux-mips@oss.sgi.com>
Subject: what is the right behavior of copy_to_user(0x0, ..., ...)?
Date: Fri, 03 May 2002 14:46:19 -0700 [thread overview]
Message-ID: <3CD3052B.1050400@mvista.com> (raw)
When running LTP, I notice that recent kernel has a kernel access fault:
<1>Unable to handle kernel paging request at virtual address 00000000, epc
== 80273860, ra == 80205aa4
Oops in fault.c:do_page_fault, line 204:
$0 : 00000000 10001f00 00000002 00000002 00000000 86df5e98 00000001 00000040
$8 : 00000000 00000000 00000001 ffffffff 00000002 802b4864 00000001 00000001
$16: 100003d8 00000000 00000002 86df5e98 00401080 10002df8 00000000 00000097
$24: 0000000a 802e7ab6 86df4000 86df5e60 7fff7c60 80205aa4
Hi : 00000000
Lo : 00000000
epc : 80273860 Not tainted
Status: 10001f03
Cause : 9080800c
....
Tracing error reveals that user process passed a NULL buffer pointer to
sys_getpeername() syscall, probably intentionally. Then it goes all the way
down to copy_to_user(0x0, ..., ...) and caused a oops as above.
As a result of oops the user process is killed. However I am not sure if this
is the right way to respond to an ill argument. copy_to_user() probably
should catch this case and return some meaningful error back to the caller.
I am not sure what is the best way to achieve this. Any thoughts?
Jun
next reply other threads:[~2002-05-03 21:46 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-05-03 21:46 Jun Sun [this message]
2002-05-03 23:23 ` what is the right behavior of copy_to_user(0x0, ..., ...)? Ralf Baechle
2002-05-03 23:41 ` Jun Sun
2002-05-04 1:40 ` Ralf Baechle
2002-05-06 18:18 ` Jun Sun
2002-05-08 3:16 ` Ralf Baechle
2002-05-07 8:47 ` Carsten Langgaard
2002-05-06 17:53 ` Ralf Baechle
2002-05-06 19:44 ` Ralf Baechle
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