netdev - Re: [PATCH v10 1/8] sched/core: Add __might_sleep

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAH5fLgiDCNj3C313JHGDrBS=14K1COOLF5vpV287pT9TM6a4zQ@mail.gmail.com>
Date: Mon, 10 Feb 2025 10:41:00 +0100
From: Alice Ryhl <aliceryhl@...gle.com>
To: FUJITA Tomonori <fujita.tomonori@...il.com>
Cc: david.laight.linux@...il.com, boqun.feng@...il.com, 
	linux-kernel@...r.kernel.org, rust-for-linux@...r.kernel.org, 
	netdev@...r.kernel.org, andrew@...n.ch, hkallweit1@...il.com, 
	tmgross@...ch.edu, ojeda@...nel.org, alex.gaynor@...il.com, gary@...yguo.net, 
	bjorn3_gh@...tonmail.com, benno.lossin@...ton.me, a.hindborg@...sung.com, 
	anna-maria@...utronix.de, frederic@...nel.org, tglx@...utronix.de, 
	arnd@...db.de, jstultz@...gle.com, sboyd@...nel.org, mingo@...hat.com, 
	peterz@...radead.org, juri.lelli@...hat.com, vincent.guittot@...aro.org, 
	dietmar.eggemann@....com, rostedt@...dmis.org, bsegall@...gle.com, 
	mgorman@...e.de, vschneid@...hat.com, tgunders@...hat.com, me@...enk.dev
Subject: Re: [PATCH v10 1/8] sched/core: Add __might_sleep_precision()

On Sat, Feb 8, 2025 at 4:01 AM FUJITA Tomonori
<fujita.tomonori@...il.com> wrote:
>
> On Fri, 7 Feb 2025 18:12:58 +0000
> David Laight <david.laight.linux@...il.com> wrote:
>
> >>  static void print_preempt_disable_ip(int preempt_offset, unsigned long ip)
> >>  {
> >>      if (!IS_ENABLED(CONFIG_DEBUG_PREEMPT))
> >> @@ -8717,7 +8699,8 @@ static inline bool resched_offsets_ok(unsigned int offsets)
> >>      return nested == offsets;
> >>  }
> >>
> >> -void __might_resched(const char *file, int line, unsigned int offsets)
> >> +static void __might_resched_precision(const char *file, int len, int line,
> >
> > For clarity that ought to be file_len.
>
> Yeah, I'll update.
>
> >> +                                  unsigned int offsets)
> >>  {
> >>      /* Ratelimiting timestamp: */
> >>      static unsigned long prev_jiffy;
> >> @@ -8740,8 +8723,10 @@ void __might_resched(const char *file, int line, unsigned int offsets)
> >>      /* Save this before calling printk(), since that will clobber it: */
> >>      preempt_disable_ip = get_preempt_disable_ip(current);
> >>
> >> -    pr_err("BUG: sleeping function called from invalid context at %s:%d\n",
> >> -           file, line);
> >> +    if (len < 0)
> >> +            len = strlen(file);
> >
> > No need for strlen(), just use a big number instead of -1.
> > Anything bigger than a sane upper limit on the filename length will do.
>
> Ah, that's right. Just passing the maximum precision (1<<15-1) works.
>
> The precision specifies the maximum length. vsnprintf() always
> iterates through a string until it reaches the maximum length or
> encounters the null terminator. So strlen() here is useless.
>
> Alice and Boqun, the above change is fine? Can I keep the tags?

I'd probably like a comment explaining the meaning of this constant
somewhere, but sure ok with me.

Alice