Re: [PATCH 1/2] clocksource: imx-tpm: fix return -ETIME when delta exceeds INT_MAX

From: Daniel Lezcano
Date: Mon Sep 02 2024 - 05:30:02 EST


On 25/07/2024 21:33, Frank Li wrote:
From: Jacky Bai <ping.bai@xxxxxxx>

In tpm_set_next_event(delta), return -ETIME by wrong cast to int when delta
is larger than INT_MAX.

For example:

tpm_set_next_event(delta = 0xffff_fffe)
{
...
next = tpm_read_counter(); // assume next is 0x10
next += delta; // next will 0xffff_fffe + 0x10 = 0x1_0000_000e
now = tpm_read_counter(); // now is 0x10
...

return (int)(next - now) <= 0 ? -ETIME : 0;
^^^^^^^^^^
0x1_0000_000e - 0x10 = 0xffff_fffe, which is -2 when
cast to int. So return -ETIME.
}

To fix this, introduce a 'prev' variable and check if 'now - prev' is
larger than delta.

Cc: <stable@xxxxxxxxxxxxxxx>
Fixes: 059ab7b82eec ("clocksource/drivers/imx-tpm: Add imx tpm timer support")
Signed-off-by: Jacky Bai <ping.bai@xxxxxxx>
Reviewed-by: Peng Fan <peng.fan@xxxxxxx>
Reviewed-by: Ye Li <ye.li@xxxxxxx>
Reviewed-by: Jason Liu <jason.hui.liu@xxxxxxx>
Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
---

Applied, thanks


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