Interrupts are enabled before the crtc datastructures are initialized.
As intel_crtc_for_pipe() is called inside interrupt handlers and can
return a NULL value, this can in rare cases lead to the following NULL
pointer dereference and panic:
RIP: 0010:handle_plane_fault+0x19/0xc0 [i915]
Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 0f
1f 44 00 00 55 48 89 e5 41 55 41 54 49 89 fc 53 48 83 ec 18 <48> 8b 1f
65 4c 8b 2d 24 90 31 ef 4c 89 6d e0 41 89 f5 48 85 db 74
RSP:
0018:ffff92b180003e50 EFLAGS: 00010086
RAX: ffffffffc0911fc0 RBX: ffffffffc06e0b90 RCX: 0000000000000005
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff92b180003e80 R08: 0000000000000005 R09: 000000010517d5f6
R10: 0000008000000041 R11: 000000010517d5f6 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 00007f72f5b72780(0000) GS:ffff8bbdcbfe9000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000102f2c000 CR4: 00000000003506f0
Kernel panic - not syncing: Fatal exception in interrupt
Kernel Offset: 0x2c800000 from 0xffffffff81000000 (relocation range:
0xffffffff80000000-0xffffffffbfffffff)
Call Trace:
<IRQ>
intel_pipe_fault_irq_handler+0x42/0xc0 [i915]
gen8_de_irq_handler+0x1ed/0xdf0 [i915]
gen8_irq_handler+0xb5/0xd0 [i915]
__handle_irq_event_percpu+0x6e/0x230
handle_irq_event+0x3a/0x90
handle_edge_irq+0xd1/0x1a0
__common_interrupt+0x48/0xe0
? generic_smp_call_function_single_interrupt+0x17/0x20
common_interrupt+0x84/0xa0
Fixes: f13011a79999 ("drm/i915: Pimp display fault reporting")
Fixes: 138d2bda4eaf ("drm/i915/display: pass display to intel_crtc_for_pipe()")
Cc: [email protected] # 6.18.x
Signed-off-by: Marcel Hamer <[email protected]>
---
drivers/gpu/drm/i915/display/intel_display_irq.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_display_irq.c
b/drivers/gpu/drm/i915/display/intel_display_irq.c
index a59b75830bd1..4ffc8789c9f3 100644
--- a/drivers/gpu/drm/i915/display/intel_display_irq.c
+++ b/drivers/gpu/drm/i915/display/intel_display_irq.c
@@ -131,6 +131,9 @@ static void intel_pipe_fault_irq_handler(struct
intel_display *display,
struct intel_crtc *crtc = intel_crtc_for_pipe(display, pipe);
const struct pipe_fault_handler *handler;
+ if (!crtc)
+ return;
+
for (handler = handlers; handler && handler->fault; handler++) {
if ((fault_errors & handler->fault) == 0)
continue;
@@ -148,7 +151,8 @@ intel_handle_vblank(struct intel_display *display, enum
pipe pipe)
{
struct intel_crtc *crtc = intel_crtc_for_pipe(display, pipe);
- drm_crtc_handle_vblank(&crtc->base);
+ if (crtc)
+ drm_crtc_handle_vblank(&crtc->base);
}
/**
@@ -425,9 +429,14 @@ static void display_pipe_crc_irq_handler(struct
intel_display *display,
u32 crc4)
{
struct intel_crtc *crtc = intel_crtc_for_pipe(display, pipe);
- struct intel_pipe_crc *pipe_crc = &crtc->pipe_crc;
+ struct intel_pipe_crc *pipe_crc;
u32 crcs[5] = { crc0, crc1, crc2, crc3, crc4 };
+ if (!crtc)
+ return;
+
+ pipe_crc = &crtc->pipe_crc;
+
trace_intel_pipe_crc(crtc, crcs);
spin_lock(&pipe_crc->lock);
@@ -465,6 +474,9 @@ static void flip_done_handler(struct intel_display *display,
{
struct intel_crtc *crtc = intel_crtc_for_pipe(display, pipe);
+ if (!crtc)
+ return;
+
spin_lock(&display->drm->event_lock);
if (crtc->flip_done_event) {
base-commit: f49a343b305c0b6c19a3b50c0bbf10bcd0e2e8fd
--
2.47.3
