[RFC PATCH linux dev-5.4 4/4] ARM: configs: aspeed-g5: Set CONFIG_FORTIFY_SOURCE=n to appease kprobes

[Patrick Williams]

On Thu, May 14, 2020 at 10:57:03PM +0930, Andrew Jeffery wrote:
> Setting CONFIG_FORTIFY_SOURCE=y and CONFIG_KPROBES=y on arm gives a panic when
> trying to insert a new probe:
> 
> $ echo r:myretprobe do_sys_open '$retval' >> /sys/kernel/debug/tracing/kprobe_events
> [   51.688589] detected buffer overflow in memcpy
> [   51.689430] ------------[ cut here ]------------
> [   51.689627] kernel BUG at lib/string.c:1096!
> [   51.689800] Internal error: Oops - BUG: 0 [#1] SMP ARM
> [   51.690107] Modules linked in:
> [   51.690442] CPU: 0 PID: 107 Comm: sh Not tainted 5.4.39-00272-ga1ee7c973659 #6
> [   51.690674] Hardware name: Generic DT based system
> [   51.691184] PC is at fortify_panic+0x18/0x20
> [   51.691371] LR is at __irq_work_queue_local+0x40/0x7c
> [   51.691575] pc : [<8083eaa4>]    lr : [<8020e0ec>]    psr: 60000013
> [   51.691812] sp : bd237cb0  ip : bd237bc0  fp : bd237cbc
> [   51.692129] r10: 00000007  r9 : 00000000  r8 : 00000060
> [   51.692395] r7 : 8011f2f0  r6 : b5092480  r5 : 7f000000  r4 : b4c53b4c
> [   51.692723] r3 : 80c04c48  r2 : 00000000  r1 : bd7c5448  r0 : 00000022
> [   51.693088] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
> [   51.693449] Control: 10c5387d  Table: b50f406a  DAC: 00000051
> [   51.693769] Process sh (pid: 107, stack limit = 0x4e9b7225)
> [   51.694126] Stack: (0xbd237cb0 to 0xbd238000)
> 
> YOLO it and disable fortified source.
> 
> Signed-off-by: Andrew Jeffery <andrew at aj.id.au>
> ---
>  arch/arm/configs/aspeed_g5_defconfig | 1 -
>  1 file changed, 1 deletion(-)

Doesn't this mean we're just hiding a bug with KPROBE code and
potentially hiding more bugs with other drivers?

-- 
Patrick Williams
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