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drm/msm: Avoid NULL dereference in msm_disp_state_print_regs()

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If the allocation in msm_disp_state_dump_regs() failed then
`block->state` can be NULL. The msm_disp_state_print_regs() function
_does_ have code to try to handle it with:

  if (*reg)
    dump_addr = *reg;

...but since "dump_addr" is initialized to NULL the above is actually
a noop. The code then goes on to dereference `dump_addr`.

Make the function print "Registers not stored" when it sees a NULL to
solve this. Since we're touching the code, fix
msm_disp_state_print_regs() not to pointlessly take a double-pointer
and properly mark the pointer as `const`.

Fixes: 98659487b8 ("drm/msm: add support to take dpu snapshot")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/619657/
Link: https://lore.kernel.org/r/20241014093605.1.Ia1217cecec9ef09eb3c6d125360cc6c8574b0e73@changeid
Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
This commit is contained in:
Douglas Anderson
2024-10-14 09:36:08 -07:00
committed by Abhinav Kumar
parent 358b762400
commit 293f532632
1 changed files with 8 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/gpu/drm/msm/disp/msm_disp_snapshot_util.c
+8 -7
View File
@@ -48,20 +48,21 @@ static void msm_disp_state_dump_regs(u32 **reg, u32 aligned_len, void __iomem *b
}
}
static void msm_disp_state_print_regs(u32 **reg, u32 len, void __iomem *base_addr,
struct drm_printer *p)
static void msm_disp_state_print_regs(const u32 *dump_addr, u32 len,
void __iomem *base_addr, struct drm_printer *p)
{
int i;
u32 *dump_addr = NULL;
void __iomem *addr;
u32 num_rows;
if (!dump_addr) {
drm_printf(p, "Registers not stored\n");
return;
}
addr = base_addr;
num_rows = len / REG_DUMP_ALIGN;
if (*reg)
dump_addr = *reg;
for (i = 0; i < num_rows; i++) {
drm_printf(p, "0x%lx : %08x %08x %08x %08x\n",
(unsigned long)(addr - base_addr),
@@ -89,7 +90,7 @@ void msm_disp_state_print(struct msm_disp_state *state, struct drm_printer *p)
list_for_each_entry_safe(block, tmp, &state->blocks, node) {
drm_printf(p, "====================%s================\n", block->name);
msm_disp_state_print_regs(&block->state, block->size, block->base_addr, p);
msm_disp_state_print_regs(block->state, block->size, block->base_addr, p);
}
drm_printf(p, "===================dpu drm state================\n");