From: Nadav Amit <nadav.amit@gmail.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: Hugh Dickins <hughd@google.com>,
Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Nadav Amit <namit@vmware.com>,
Sean Christopherson <seanjc@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
x86@kernel.org
Subject: [RFC 1/6] vdso/extable: fix calculation of base
Date: Wed, 24 Feb 2021 23:29:05 -0800 [thread overview]
Message-ID: <20210225072910.2811795-2-namit@vmware.com> (raw)
In-Reply-To: <20210225072910.2811795-1-namit@vmware.com>
From: Nadav Amit <namit@vmware.com>
Apparently, the assembly considers __ex_table as the location when the
pushsection directive was issued. Therefore when there is more than a
single entry in the vDSO exception table, the calculations of the base
and fixup are wrong.
Fix the calculations of the expected fault IP and new IP by adjusting
the base after each entry.
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: x86@kernel.org
Signed-off-by: Nadav Amit <namit@vmware.com>
---
arch/x86/entry/vdso/extable.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/entry/vdso/extable.c b/arch/x86/entry/vdso/extable.c
index afcf5b65beef..c81e78636220 100644
--- a/arch/x86/entry/vdso/extable.c
+++ b/arch/x86/entry/vdso/extable.c
@@ -32,7 +32,7 @@ bool fixup_vdso_exception(struct pt_regs *regs, int trapnr,
nr_entries = image->extable_len / (sizeof(*extable));
extable = image->extable;
- for (i = 0; i < nr_entries; i++) {
+ for (i = 0; i < nr_entries; i++, base += sizeof(*extable)) {
if (regs->ip == base + extable[i].insn) {
regs->ip = base + extable[i].fixup;
regs->di = trapnr;
--
2.25.1
next prev parent reply other threads:[~2021-02-25 7:35 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-25 7:29 [RFC 0/6] x86: prefetch_page() vDSO call Nadav Amit
2021-02-25 7:29 ` Nadav Amit [this message]
2021-02-25 21:16 ` [RFC 1/6] vdso/extable: fix calculation of base Sean Christopherson
2021-02-26 17:24 ` Nadav Amit
2021-02-26 17:47 ` Sean Christopherson
2021-02-28 9:20 ` Nadav Amit
2021-02-25 7:29 ` [RFC 2/6] x86/vdso: add mask and flags to extable Nadav Amit
2021-02-25 7:29 ` [RFC 3/6] x86/vdso: introduce page_prefetch() Nadav Amit
2021-02-25 7:29 ` [RFC 4/6] mm/swap_state: respect FAULT_FLAG_RETRY_NOWAIT Nadav Amit
2021-02-25 7:29 ` [RFC 5/6] mm: use lightweight reclaim on FAULT_FLAG_RETRY_NOWAIT Nadav Amit
2021-02-25 7:29 ` [PATCH 6/6] testing/selftest: test vDSO prefetch_page() Nadav Amit
2021-02-25 8:40 ` [RFC 0/6] x86: prefetch_page() vDSO call Peter Zijlstra
2021-02-25 8:52 ` Nadav Amit
2021-02-25 9:32 ` Nadav Amit
2021-02-25 9:55 ` Peter Zijlstra
2021-02-25 12:16 ` Matthew Wilcox
2021-02-25 16:56 ` Nadav Amit
2021-02-25 17:32 ` Matthew Wilcox
2021-02-25 17:53 ` Nadav Amit
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