From: Ingo Molnar <mingo@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linuxfoundation.org>,
x86@kernel.org, Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Borislav Petkov <bp@alien8.de>,
Dominik Brodowski <linux@dominikbrodowski.net>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: Re: [patch 1/3] x86/ldt: Free the right LDT memory in write_ldt() error path
Date: Sat, 30 Dec 2017 22:33:37 +0100 [thread overview]
Message-ID: <20171230213337.tns3dtj7z526bvf2@gmail.com> (raw)
In-Reply-To: <20171230211829.508293470@linutronix.de>
* Thomas Gleixner <tglx@linutronix.de> wrote:
> The error path in write_ldt() frees the already installed LDT memory
> instead of the newly allocated which cannot be installed.
s/newly allocated
/newly allocated one
>
> Fixes: f55f0501cbf6 ("x86/pti: Put the LDT in its own PGD if PTI is on")
> Reported-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> arch/x86/kernel/ldt.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- a/arch/x86/kernel/ldt.c
> +++ b/arch/x86/kernel/ldt.c
> @@ -421,7 +421,7 @@ static int write_ldt(void __user *ptr, u
> */
> error = map_ldt_struct(mm, new_ldt, old_ldt ? !old_ldt->slot : 0);
> if (error) {
> - free_ldt_struct(old_ldt);
> + free_ldt_struct(new_ldt);
> goto out_unlock;
> }
>
This bug kind of scares me ...
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Thanks,
Ingo
next prev parent reply other threads:[~2017-12-30 21:33 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-30 21:13 [patch 0/3] x86/pti: Fix various fallout Thomas Gleixner
2017-12-30 21:13 ` [patch 1/3] x86/ldt: Free the right LDT memory in write_ldt() error path Thomas Gleixner
2017-12-30 21:33 ` Ingo Molnar [this message]
2017-12-31 10:24 ` [patch V2 1/3] x86/ldt: Plug memory leak in " Thomas Gleixner
2017-12-31 15:23 ` Andy Lutomirski
2017-12-30 21:13 ` [patch 2/3] x86/smpboot: Remove stale tlb flush invocations Thomas Gleixner
2017-12-30 21:32 ` Ingo Molnar
2017-12-30 21:13 ` [patch 3/3] x86/mm: Remove preempt_disable/enable() from __native_flush_tlb() Thomas Gleixner
2017-12-30 21:31 ` Ingo Molnar
2017-12-30 21:35 ` [patch 0/3] x86/pti: Fix various fallout Ingo Molnar
2017-12-30 22:06 ` Linus Torvalds
2017-12-31 2:23 ` Andy Lutomirski
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