From: Will Deacon <will@kernel.org>
To: Liam Howlett <liam.howlett@oracle.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Julien Grall <julien.grall@arm.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"bpf@vger.kernel.org" <bpf@vger.kernel.org>
Subject: Re: [PATCH 3/3] arch/arm64/kernel/traps: Use find_vma_intersection() in traps for setting si_code
Date: Thu, 22 Apr 2021 13:53:34 +0100 [thread overview]
Message-ID: <20210422125334.GB1521@willie-the-truck> (raw)
In-Reply-To: <20210420165001.3790670-3-Liam.Howlett@Oracle.com>
On Tue, Apr 20, 2021 at 04:50:13PM +0000, Liam Howlett wrote:
> find_vma() will continue to search upwards until the end of the virtual
> memory space. This means the si_code would almost never be set to
> SEGV_MAPERR even when the address falls outside of any VMA. The result
> is that the si_code is not reliable as it may or may not be set to the
> correct result, depending on where the address falls in the address
> space.
>
> Using find_vma_intersection() allows for what is intended by only
> returning a VMA if it falls within the range provided, in this case a
> window of 1.
>
> Fixes: bd35a4adc413 (arm64: Port SWP/SWPB emulation support from arm)
> Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
> ---
> arch/arm64/kernel/traps.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
> index a05d34f0e82a..a44007904a64 100644
> --- a/arch/arm64/kernel/traps.c
> +++ b/arch/arm64/kernel/traps.c
> @@ -383,9 +383,10 @@ void force_signal_inject(int signal, int code, unsigned long address, unsigned i
> void arm64_notify_segfault(unsigned long addr)
> {
> int code;
> + unsigned long ut_addr = untagged_addr(addr);
>
> mmap_read_lock(current->mm);
> - if (find_vma(current->mm, untagged_addr(addr)) == NULL)
> + if (find_vma_intersection(current->mm, ut_addr, ut_addr + 1) == NULL)
> code = SEGV_MAPERR;
> else
> code = SEGV_ACCERR;
I'm not seeing how this addresses VM_GROWSDOWN as Catalin mentioned before.
Will
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next prev parent reply other threads:[~2021-04-22 12:55 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-20 16:50 [PATCH 1/3] arm64: armv8_deprecated: Fix swp_handler() signal generation Liam Howlett
2021-04-20 16:50 ` [PATCH 2/3] arm64: signal: sigreturn() and rt_sigreturn() sometime returns the wrong signals Liam Howlett
2021-04-22 12:48 ` Will Deacon
2021-04-22 18:22 ` Eric W. Biederman
2021-04-22 19:24 ` Liam Howlett
2021-04-23 18:17 ` Eric W. Biederman
2021-04-23 20:03 ` Liam Howlett
2021-04-29 17:52 ` Eric W. Biederman
2021-04-30 18:48 ` Liam Howlett
2021-04-30 19:57 ` Eric W. Biederman
2021-04-30 20:31 ` Liam Howlett
2021-04-20 16:50 ` [PATCH 3/3] arch/arm64/kernel/traps: Use find_vma_intersection() in traps for setting si_code Liam Howlett
2021-04-22 12:53 ` Will Deacon [this message]
2021-04-22 18:56 ` Liam Howlett
[not found] ` <202104210515.VoF3YT1J-lkp@intel.com>
2021-04-21 15:47 ` [PATCH 1/3] arm64: armv8_deprecated: Fix swp_handler() signal generation Liam Howlett
2021-04-22 12:59 ` Will Deacon
2021-04-23 1:00 ` Liam Howlett
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