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From: Liam Howlett <liam.howlett@oracle.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	 Julien Grall <julien.grall@arm.com>
Cc: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Liam Howlett <liam.howlett@oracle.com>,
	"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: [PATCH 3/3] arch/arm64/kernel/traps: Use find_vma_intersection() in traps for setting si_code
Date: Tue, 20 Apr 2021 16:50:13 +0000	[thread overview]
Message-ID: <20210420165001.3790670-3-Liam.Howlett@Oracle.com> (raw)
In-Reply-To: <20210420165001.3790670-1-Liam.Howlett@Oracle.com>

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;
-- 
2.30.2

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  parent reply	other threads:[~2021-04-20 16:54 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 ` Liam Howlett [this message]
2021-04-22 12:53   ` [PATCH 3/3] arch/arm64/kernel/traps: Use find_vma_intersection() in traps for setting si_code Will Deacon
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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