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x86/static_call: Serialize __static_call_fixup() properly

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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@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Thomas Gleixner
2022-07-12 14:01:06 +02:00
committed by Greg Kroah-Hartman
parent eb38964b6f
commit c035ca88b0
1 changed files with 8 additions and 5 deletions
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13
arch/x86/kernel/static_call.c
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@@ -20,7 +20,8 @@ static const u8 tramp_ud[] = { 0x0f, 0xb9, 0xcc };
static const u8 retinsn[] = { RET_INSN_OPCODE, 0xcc, 0xcc, 0xcc, 0xcc }; 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; int size = CALL_INSN_SIZE;
const void *code; const void *code;
@@ -49,7 +50,7 @@ static void __ref __static_call_transform(void *insn, enum insn_type type, void
if (memcmp(insn, code, size) == 0) if (memcmp(insn, code, size) == 0)
return; return;
if (unlikely(system_state == SYSTEM_BOOTING)) if (system_state == SYSTEM_BOOTING || modinit)
return text_poke_early(insn, code, size); return text_poke_early(insn, code, size);
text_poke_bp(insn, code, size, NULL); text_poke_bp(insn, code, size, NULL);
@@ -96,12 +97,12 @@ void arch_static_call_transform(void *site, void *tramp, void *func, bool tail)
if (tramp) { if (tramp) {
__static_call_validate(tramp, true); __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) { if (IS_ENABLED(CONFIG_HAVE_STATIC_CALL_INLINE) && site) {
__static_call_validate(site, tail); __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); mutex_unlock(&text_mutex);
@@ -127,8 +128,10 @@ bool __static_call_fixup(void *tramp, u8 op, void *dest)
return false; return false;
} }
mutex_lock(&text_mutex);
if (op == RET_INSN_OPCODE || dest == &__x86_return_thunk) 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; return true;
} }