From: Nicholas Piggin <npiggin@xxxxxxxxx>
[ Upstream commit 5567b1ee29b7a83e8c01d99d34b5bbd306ce0bcf ]
The early bad fault or key fault test in do_hash_fault() ends up calling
into ___do_page_fault without having gone through an interrupt handler
wrapper (except the initial _RAW one). This can end up calling local irq
functions while the interrupt has not been reconciled, which will likely
cause crashes and it trips up on a later patch that adds more assertions.
pkey_exec_prot from selftests causes this path to be executed.
There is no real reason to run the in_nmi() test should be performed
before the key fault check. In fact if a perf interrupt in the hash
fault code did a stack walk that was made to take a key fault somehow
then running ___do_page_fault could possibly cause another hash fault
causing problems. Move the in_nmi() test first, and then do everything
else inside the regular interrupt handler function.
Fixes: 3a96570ffceb ("powerpc: convert interrupt handlers to use wrappers")
Reported-by: Sachin Sant <sachinp@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
Tested-by: Sachin Sant <sachinp@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210630074621.2109197-2-npiggin@xxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/powerpc/mm/book3s64/hash_utils.c | 24 +++++++++++-------------
1 file changed, 11 insertions(+), 13 deletions(-)
diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
index 96d9aa164007..ac5720371c0d 100644
--- a/arch/powerpc/mm/book3s64/hash_utils.c
+++ b/arch/powerpc/mm/book3s64/hash_utils.c
@@ -1522,8 +1522,8 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap,
}
EXPORT_SYMBOL_GPL(hash_page);
-DECLARE_INTERRUPT_HANDLER_RET(__do_hash_fault);
-DEFINE_INTERRUPT_HANDLER_RET(__do_hash_fault)
+DECLARE_INTERRUPT_HANDLER(__do_hash_fault);
+DEFINE_INTERRUPT_HANDLER(__do_hash_fault)
{
unsigned long ea = regs->dar;
unsigned long dsisr = regs->dsisr;
@@ -1533,6 +1533,11 @@ DEFINE_INTERRUPT_HANDLER_RET(__do_hash_fault)
unsigned int region_id;
long err;
+ if (unlikely(dsisr & (DSISR_BAD_FAULT_64S | DSISR_KEYFAULT))) {
+ hash__do_page_fault(regs);
+ return;
+ }
+
region_id = get_region_id(ea);
if ((region_id == VMALLOC_REGION_ID) || (region_id == IO_REGION_ID))
mm = &init_mm;
@@ -1571,9 +1576,10 @@ DEFINE_INTERRUPT_HANDLER_RET(__do_hash_fault)
bad_page_fault(regs, SIGBUS);
}
err = 0;
- }
- return err;
+ } else if (err) {
+ hash__do_page_fault(regs);
+ }
}
/*
@@ -1582,13 +1588,6 @@ DEFINE_INTERRUPT_HANDLER_RET(__do_hash_fault)
*/
DEFINE_INTERRUPT_HANDLER_RAW(do_hash_fault)
{
- unsigned long dsisr = regs->dsisr;
-
- if (unlikely(dsisr & (DSISR_BAD_FAULT_64S | DSISR_KEYFAULT))) {
- hash__do_page_fault(regs);
- return 0;
- }
-
/*
* If we are in an "NMI" (e.g., an interrupt when soft-disabled), then
* don't call hash_page, just fail the fault. This is required to
@@ -1607,8 +1606,7 @@ DEFINE_INTERRUPT_HANDLER_RAW(do_hash_fault)
return 0;
}
- if (__do_hash_fault(regs))
- hash__do_page_fault(regs);
+ __do_hash_fault(regs);
return 0;
}
--
2.30.2
