[PATCH] arm: uprobes: Don't hook on thumb instructions

[Marc Zyngier]

Hi Fredrik,

On  Mon, 18 May 2020, Fredrik Strupe wrote:
> Since uprobes is not supported for thumb, check that the thumb bit is
> not set when matching the uprobes instruction hooks.
>
> The Arm UDF instructions used for uprobes triggering
> (UPROBE_SWBP_ARM_INSN and UPROBE_SS_ARM_INSN) coincidentally share the
> same encoding as a pair of unallocated 32-bit thumb instructions (not
> UDF) when the condition code is 0b1111 (0xf). This in effect makes it
> possible to trigger the uprobes functionality from thumb, and at that
> using two unallocated instructions which are not permanently
> undefined.
>
> Signed-off-by: Fredrik Strupe <fredrik at strupe.net
> Fixes: c7edc9e326d5 ("ARM: add uprobes support")

It looks like we dropped the ball on this patch. Could you please add
it to Russell's patch system, together with a Cc: stable?

Otherwise, just say the word and I'll do it for you.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.