[Bug 216905] Kernel won't compile with KASAN

[bugzill...@kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=216905

Dmitry Vyukov (dvy...@google.com) changed:

What |Removed |Added
----------------------------------------------------------------------------
CC| |dvy...@google.com,
| |kasa...@googlegroups.com
Component|Other |Sanitizers
Assignee|ak...@linux-foundation.org |mm_sanitizers@kernel-bugs.k
| |ernel.org

--
You may reply to this email to add a comment.

You are receiving this mail because:
You are on the CC list for the bug.

[bugzill...@kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=216905

--- Comment #5 from Dmitry Vyukov (dvy...@google.com) ---
Maybe we should add noinline_for_stack to ecc_point_double_jacobian() function
declaration:
https://elixir.bootlin.com/linux/v6.2-rc3/source/include/linux/compiler_types.h#L192

it's called from ecc_point_mult_shamir():
https://elixir.bootlin.com/linux/v6.2-rc3/source/crypto/ecc.c#L1396

Though I am not sure about performance impact in non-KASAN build.

Meanwhile you may try gcc 10.2. syzbot uses it with KASAN and builds seem to be
fine.

[bugzill...@kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=216905

--- Comment #6 from Theodore Tso (ty...@mit.edu) ---
On Mon, Jan 09, 2023 at 08:58:41PM -0800, Robert Dinse wrote:
>
> Increasing to 2048 did allow kernels to compile with KASAN enabled. I
> am curious why e-mail only? It would seem bugzilla, a public forum would
> make this fix available to others who may be experiencing the same or
> related problems.

Not all kernel developers pay attention to bugzilla. (In fact, most
kernel developers do not.)

>  Interestingly, I could not locate the symbol with
> xconfig, had to hand edit the .config file in deference to the fact that it
> tells you not to.

If you search for FRAME_WARN in menuconfig ('/', followed by
"FRAME_WARN", followed by return), it will report:

Symbol: FRAME_WARN [=2048]
Type : integer
Range : [0 8192]
Defined at lib/Kconfig.debug:395
Prompt: Warn for stack frames larger than
Locationf
-> Kernel hacking
-> Compile-time checks and compiler options
(1) -> Warn for stack frames larger than (FRAME_WARN [=2048])


That being said, you can edit the .config file if you know what you
are doing. But if it breaks, you get to keep both pieces, since there
aren't the safety checks and guardrails of the supported paths. For
novices, I recommend saving a copy of .config before editing the
.config, and then afterwards, run "make oldconfig", and then diff the
resulting .config with the saved copy to make sure there aren't any
unexpected changes.

Cheers,

- Ted

[bugzill...@kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=216905

--- Comment #7 from Robert Dinse (nan...@eskimo.com) ---
I used xconfig and used control-F and then searched on the same term, didn't
find. But moot at this point. Kernel is built and installed on one machine,
will install on the other two NFS servers this friday, they have more mission
critical apps so can not boot them during the business week.

[bugzill...@kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=216905

Robert Dinse (nan...@eskimo.com) changed:

What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution|--- |ANSWERED

--- Comment #8 from Robert Dinse (nan...@eskimo.com) ---
Since this got around the compile issue, I am closing this ticket.