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From: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
To: Eric Biggers <ebiggers@kernel.org>
Cc: stable@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Kees Cook <keescook@chromium.org>, SeongJae Park <sj@kernel.org>,
	Seth Jenkins <sethjenkins@google.com>,
	Jann Horn <jannh@google.com>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org,
	Luis Chamberlain <mcgrof@kernel.org>,
	Vegard Nossum <vegard.nossum@oracle.com>,
	Darren Kenny <darren.kenny@oracle.com>
Subject: Re: [PATCH 5.15 13/20] exit: Put an upper limit on how often we can oops
Date: Thu, 26 Jan 2023 00:29:11 +0530	[thread overview]
Message-ID: <f9566605-c4f8-0306-7f07-86b9e0abebfd@oracle.com> (raw)
In-Reply-To: <Y9F4hxtZnE2GssUo@sol.localdomain>

Hi Eric,

On 26/01/23 12:14 am, Eric Biggers wrote:
> Hi Harshit,
> 
> On Wed, Jan 25, 2023 at 07:39:10PM +0530, Harshit Mogalapalli wrote:
>>
>> Thanks for the backports.
>>
>> I have tried backporting the oops_limit patches to LTS 5.15.y and had a
>> similar set of patches, just want to add a note here on an alternate way for
>> backporting this patch without resolving conflicts manually:
>>
>> Here is the sequence:
>>
>> * Patch 12:  [panic: Separate sysctl logic from CONFIG_SMP]
>> --> Cherry-pick Commit: 05ea0424f0e2 ("exit: Move oops specific logic from
>> do_exit into make_task_dead") upstream
>> --> Cherry-pick Commit: de77c3a5b95c ("exit: Move force_uaccess back into
>> do_exit") upstream
>> * Patch 13 which is Commit: d4ccd54d28d3 ("exit: Put an upper limit on how
>> often we can oops") upstream, will be a clean cherry-pick.
>>
>> The benefit may be making future backports simpler in make_task_dead().
>>
>> This was the only difference, so your backport looks good to me.
>>
> 
> It's certainly an option.  The reason why I didn't do it that way is to reduce
> the impact of any potential bugs where do_exit() is still called when the new
> make_task_dead() function should be used instead.  With my series, the effect is
> just that oops_limit won't take effect in such cases.  If we also backported
> commit 05ea0424f0e2 ("exit: Move oops specific logic from do_exit into
> make_task_dead"), then do_exit() will lose various other things, such as
> panicing when called from an interrupt handler.  That would increase the chance
> of regressions, unless we made absolutely sure that everywhere that should be
> using make_task_dead() is indeed using it instead of do_exit().
> 
> Commit 0e25498f8cd4 ("exit: Add and use make_task_dead."), which I backported,
> did the vast majority of conversions to make_task_dead().
> 
> Some architectures still have uses of do_exit() that got cleaned up later,
> though.  It seems it was mostly unreachable code, and some cases that should
> have been doing something else such as BUG() or sending a signal to userspace.
> So, generally not super important cases.
> 

Thanks a lot for explaining!

> Still, getting all that would bring in many more patches.  We could do that, but
> since this is already a 20-patch series, I wanted to limit the scope a bit.
> These extra patches could always be backported later on top of this if desired.
> 

Sure.

Regards,
Harshit
> - Eric

  reply	other threads:[~2023-01-25 18:59 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-24 18:50 [PATCH 5.15 00/20] Backport oops_limit to 5.15 Eric Biggers
2023-01-24 18:50 ` [PATCH 5.15 01/20] sysctl: add a new register_sysctl_init() interface Eric Biggers
2023-01-24 18:50 ` [PATCH 5.15 02/20] kernel/panic: move panic sysctls to its own file Eric Biggers
2023-01-24 18:50 ` [PATCH 5.15 03/20] panic: unset panic_on_warn inside panic() Eric Biggers
2023-01-24 18:50 ` [PATCH 5.15 04/20] ubsan: no need to unset panic_on_warn in ubsan_epilogue() Eric Biggers
2023-01-24 18:50 ` [PATCH 5.15 05/20] kasan: no need to unset panic_on_warn in end_report() Eric Biggers
2023-01-24 18:50 ` [PATCH 5.15 06/20] exit: Add and use make_task_dead Eric Biggers
2023-01-24 18:50 ` [PATCH 5.15 07/20] objtool: Add a missing comma to avoid string concatenation Eric Biggers
2023-01-24 18:50 ` [PATCH 5.15 08/20] hexagon: Fix function name in die() Eric Biggers
2023-01-24 18:50 ` [PATCH 5.15 09/20] h8300: Fix build errors from do_exit() to make_task_dead() transition Eric Biggers
2023-01-24 18:51 ` [PATCH 5.15 10/20] csky: Fix function name in csky_alignment() and die() Eric Biggers
2023-01-24 18:51 ` [PATCH 5.15 11/20] ia64: make IA64_MCA_RECOVERY bool instead of tristate Eric Biggers
2023-01-24 18:51 ` [PATCH 5.15 12/20] panic: Separate sysctl logic from CONFIG_SMP Eric Biggers
2023-01-24 18:51 ` [PATCH 5.15 13/20] exit: Put an upper limit on how often we can oops Eric Biggers
2023-01-25 14:09   ` Harshit Mogalapalli
2023-01-25 18:44     ` Eric Biggers
2023-01-25 18:59       ` Harshit Mogalapalli [this message]
2023-01-24 18:51 ` [PATCH 5.15 14/20] exit: Expose "oops_count" to sysfs Eric Biggers
2023-01-24 18:51 ` [PATCH 5.15 15/20] exit: Allow oops_limit to be disabled Eric Biggers
2023-01-24 18:51 ` [PATCH 5.15 16/20] panic: Consolidate open-coded panic_on_warn checks Eric Biggers
2023-01-24 18:51 ` [PATCH 5.15 17/20] panic: Introduce warn_limit Eric Biggers
2023-01-24 18:51 ` [PATCH 5.15 18/20] panic: Expose "warn_count" to sysfs Eric Biggers
2023-01-24 18:51 ` [PATCH 5.15 19/20] docs: Fix path paste-o for /sys/kernel/warn_count Eric Biggers
2023-01-24 18:51 ` [PATCH 5.15 20/20] exit: Use READ_ONCE() for all oops/warn limit reads Eric Biggers
2023-01-27  2:08 ` [PATCH 5.15 00/20] Backport oops_limit to 5.15 Sasha Levin

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