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| author | Nicholas Piggin <npiggin@gmail.com> | 2021-10-26 22:25:31 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-10-27 22:33:47 +1100 |
| commit | 4a5cb51f3db4be547225a4bce7a43d41b231382b (patch) | |
| tree | c3c3001c8c95640b33737c965d04f17d4898b39b /arch/powerpc/kernel/interrupt.c | |
| parent | b949d009dd52ecdced248889cf11297677f9e8a6 (diff) | |
| download | lwn-4a5cb51f3db4be547225a4bce7a43d41b231382b.tar.gz lwn-4a5cb51f3db4be547225a4bce7a43d41b231382b.zip | |
powerpc/64s/interrupt: Fix check_return_regs_valid() false positive
The check_return_regs_valid() can cause a false positive if the return
regs are marked as norestart and they are an HSRR type interrupt,
because the low bit in the bottom of regs->trap causes interrupt type
matching to fail.
This can occcur for example on bare metal with a HV privileged doorbell
interrupt that causes a signal, but do_signal returns early because
get_signal() fails, and takes the "No signal to deliver" path. In this
case no signal was delivered so the return location is not changed so
return SRRs are not invalidated, yet set_trap_norestart is called, which
messes up the match. Building go-1.16.6 is known to reproduce this.
Fix it by using the TRAP() accessor which masks out the low bit.
Fixes: 6eaaf9de3599 ("powerpc/64s/interrupt: Check and fix srr_valid without crashing")
Cc: stable@vger.kernel.org # v5.14+
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211026122531.3599918-1-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc/kernel/interrupt.c')
| -rw-r--r-- | arch/powerpc/kernel/interrupt.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c index de10a2697258..835b626cd476 100644 --- a/arch/powerpc/kernel/interrupt.c +++ b/arch/powerpc/kernel/interrupt.c @@ -266,7 +266,7 @@ static void check_return_regs_valid(struct pt_regs *regs) if (trap_is_scv(regs)) return; - trap = regs->trap; + trap = TRAP(regs); // EE in HV mode sets HSRRs like 0xea0 if (cpu_has_feature(CPU_FTR_HVMODE) && trap == INTERRUPT_EXTERNAL) trap = 0xea0; |