From: John Whitney <john.whitney@timesys•com>
To: "Mailing List: linuxppc-dev" <linuxppc-dev@lists•linuxppc.org>
Subject: NULL-pointer dereference in ELF core dump, and proposed fix
Date: Tue, 23 Dec 2003 09:46:19 -0500 [thread overview]
Message-ID: <BC0DBF6B.3126%john.whitney@timesys.com> (raw)
Hello,
As stated in the subject, I've found a NULL-pointer dereference in the ELF
core dump code path, and wanted comments on my proposed solution.
In fs/binfmt_elf.c, elf_core_dump() calls elf_dump_thread_status().
elf_dump_thread_status calls elf_core_copy_task_fpregs() (elfcore.h), with a
second parameter (struct pt_regs *regs) of NULL.
This inlined routine in turn calls dump_fpu() (arch/ppc/kernel/process.c),
again with a NULL "regs" parameter.
dump_fpu immediately dereferences the regs parameter with the line:
if (regs->msr & MSR_FP)
giveup_fpu (current);
This, obviously, causes a kernel oops. My proposed solution to this problem
is to change the above line of code to
if (last_task_used_math == current)
giveup_fpu (current);
Anyone see any problems with this change?
Thanks,
John Whitney
** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/
next reply other threads:[~2003-12-23 14:46 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-12-23 14:46 John Whitney [this message]
2003-12-24 3:51 ` NULL-pointer dereference in ELF core dump, and proposed fix Benjamin Herrenschmidt
2003-12-30 6:34 ` A question on kernel clock: John Zhou
2003-12-30 10:22 ` Wolfgang Denk
2003-12-30 10:45 ` John Zhou
2003-12-30 18:49 ` Wolfgang Denk
2003-12-30 21:07 ` Dale Harris
2003-12-30 21:40 ` Wolfgang Denk
2003-12-31 4:15 ` John Zhou
2003-12-31 2:44 ` John Zhou
2003-12-31 2:44 ` about small dhcp client/server and http client/server John Zhou
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