From: Andrew Morton <akpm@linux-foundation.org>
To: "chunlei.wang" <Chunlei.wang@mediatek.com>
Cc: weiwei.zhang@mediatek.com, wsd_upstream@mediatek.com,
Peter Zijlstra <peterz@infradead.org>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
Oleg Nesterov <oleg@redhat.com>,
linux-mediatek@lists.infradead.org,
Matthias Brugger <matthias.bgg@gmail.com>,
Will Deacon <will@kernel.org>
Subject: Re: [PATCH] siganl: ignore other signals when doing coredump
Date: Thu, 23 Jul 2020 17:51:26 -0700 [thread overview]
Message-ID: <20200723175126.cf6a660e46c8da26b1293eb4@linux-foundation.org> (raw)
In-Reply-To: <1595487143.29785.9.camel@mbjsdccf07>
On Thu, 23 Jul 2020 14:52:23 +0800 "chunlei.wang" <Chunlei.wang@mediatek.com> wrote:
> do_coredump flow is interrupted by SIGKILL,
> causing the coredump to be truncated.
>
Please tell us much more about why you think Linux would benefit from
this change. Precisely what operational problems are you seeing with
the current code?
> ---
> arch/Kconfig | 12 ++++++++++++
> kernel/signal.c | 8 ++++++++
> 2 files changed, 20 insertions(+)
>
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 8cc35dc556c7..559eac47093e 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -834,6 +834,18 @@ config OLD_SIGACTION
> config COMPAT_OLD_SIGACTION
> bool
>
> +config IGNORE_ANY_SIGNALS
> + tristate "ignore any signals when coredump is doing"
> + default n
> + help
> + The sigkill is very special. If a process receives a sigkill, it
> will
> + immediately respond to the sigkill. When a process is abnormal and
> + collecting coredump, the do_coredump flow will be interrupted by
> + SIGKILL, causing the coredump to be truncated. This truncated
> coredump
> + is incomplete, and also gdb can't load.
> + Maybe we can ignore any signlas when process is collecting coredump.
> + This config can decide whether to ignore any signals.
> +
> config COMPAT_32BIT_TIME
> bool "Provide system calls for 32-bit time_t"
> default !64BIT || COMPAT
> diff --git a/kernel/signal.c b/kernel/signal.c
> index 5ca48cc5da76..ccae3c84eb6d 100644
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -903,6 +903,14 @@ static bool prepare_signal(int sig, struct
> task_struct *p, bool force)
> sigset_t flush;
>
> if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) {
> +
> +#if defined CONFIG_IGNORE_ANY_SIGNALS
> + if (signal->flags & SIGNAL_GROUP_COREDUMP) {
> + pr_debug("[%d:%s] skip sig %d due to coredump is doing\n",
> + p->pid, p->comm, sig);
> + return false;
> + }
> +#endif
> if (!(signal->flags & SIGNAL_GROUP_EXIT))
> return sig == SIGKILL;
> /*
> --
> 2.18.0
>
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next prev parent reply other threads:[~2020-07-24 0:51 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-23 6:52 [PATCH] siganl: ignore other signals when doing coredump chunlei.wang
2020-07-24 0:51 ` Andrew Morton [this message]
2020-07-31 8:54 ` chunlei.wang
2020-08-03 19:17 ` Oleg Nesterov
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