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Date: Tue, 12 Jul 2022 20:39:36 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
Borislav Petkov <bp@...e.de>
Subject: [PATCH 5.10 130/130] x86/static_call: Serialize __static_call_fixup() properly
From: Thomas Gleixner <tglx@...utronix.de>
commit c27c753ea6fd1237f4f96abf8b623d7bab505513 upstream.
__static_call_fixup() invokes __static_call_transform() without holding
text_mutex, which causes lockdep to complain in text_poke_bp().
Adding the proper locking cures that, but as this is either used during
early boot or during module finalizing, it's not required to use
text_poke_bp(). Add an argument to __static_call_transform() which tells
it to use text_poke_early() for it.
Fixes: ee88d363d156 ("x86,static_call: Use alternative RET encoding")
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Borislav Petkov <bp@...e.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
arch/x86/kernel/static_call.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
--- a/arch/x86/kernel/static_call.c
+++ b/arch/x86/kernel/static_call.c
@@ -20,7 +20,8 @@ static const u8 tramp_ud[] = { 0x0f, 0xb
static const u8 retinsn[] = { RET_INSN_OPCODE, 0xcc, 0xcc, 0xcc, 0xcc };
-static void __ref __static_call_transform(void *insn, enum insn_type type, void *func)
+static void __ref __static_call_transform(void *insn, enum insn_type type,
+ void *func, bool modinit)
{
int size = CALL_INSN_SIZE;
const void *code;
@@ -49,7 +50,7 @@ static void __ref __static_call_transfor
if (memcmp(insn, code, size) == 0)
return;
- if (unlikely(system_state == SYSTEM_BOOTING))
+ if (system_state == SYSTEM_BOOTING || modinit)
return text_poke_early(insn, code, size);
text_poke_bp(insn, code, size, NULL);
@@ -96,12 +97,12 @@ void arch_static_call_transform(void *si
if (tramp) {
__static_call_validate(tramp, true);
- __static_call_transform(tramp, __sc_insn(!func, true), func);
+ __static_call_transform(tramp, __sc_insn(!func, true), func, false);
}
if (IS_ENABLED(CONFIG_HAVE_STATIC_CALL_INLINE) && site) {
__static_call_validate(site, tail);
- __static_call_transform(site, __sc_insn(!func, tail), func);
+ __static_call_transform(site, __sc_insn(!func, tail), func, false);
}
mutex_unlock(&text_mutex);
@@ -127,8 +128,10 @@ bool __static_call_fixup(void *tramp, u8
return false;
}
+ mutex_lock(&text_mutex);
if (op == RET_INSN_OPCODE || dest == &__x86_return_thunk)
- __static_call_transform(tramp, RET, NULL);
+ __static_call_transform(tramp, RET, NULL, true);
+ mutex_unlock(&text_mutex);
return true;
}
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