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From: Borislav Petkov <bp@alien8.de>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: Jue Wang <juew@google.com>, Ding Hui <dinghui@sangfor.com.cn>,
	naoya.horiguchi@nec.com, osalvador@suse.de,
	Youquan Song <youquan.song@intel.com>,
	huangcun@sangfor.com.cn, x86@kernel.org,
	linux-edac@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/3] x86/mce: Avoid infinite loop for copy from user recovery
Date: Sun, 22 Aug 2021 16:46:14 +0200	[thread overview]
Message-ID: <YSJjNlTJiBx1v1SS@zn.tnic> (raw)
In-Reply-To: <20210820203356.GA1623896@agluck-desk2.amr.corp.intel.com>

On Fri, Aug 20, 2021 at 01:33:56PM -0700, Luck, Tony wrote:
> The new version (thanks to All fixing iov_iter.c) now does
> exactly what POSIX says should happen.  If I have a buffer
> with poison at offset 213, and I do this:
> 
> 	ret = write(fd, buf, 512);
> 
> Then the return from write is 213, and the first 213 bytes
> from the buffer appear in the file, and the file size is
> incremented by 213 (assuming the write started with the lseek
> offset at the original size of the file).

... and the user still gets a SIGBUS so that it gets a chance to handle
the encountered poison? I.e., not retry the write for the remaining 512
- 213 bytes?

If so, do we document that somewhere so that application writers can
know what they should do in such cases?

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

  reply	other threads:[~2021-08-22 14:45 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-06 19:06 [PATCH 0/3] More machine check recovery fixes Tony Luck
2021-07-06 19:06 ` [PATCH 1/3] x86/mce: Change to not send SIGBUS error during copy from user Tony Luck
2021-07-06 19:06 ` [PATCH 2/3] x86/mce: Avoid infinite loop for copy from user recovery Tony Luck
2021-07-06 19:06 ` [PATCH 3/3] x86/mce: Drop copyin special case for #MC Tony Luck
2021-08-18  0:29 ` [PATCH v2 0/3] More machine check recovery fixes Tony Luck
2021-08-18  0:29   ` [PATCH v2 1/3] x86/mce: Avoid infinite loop for copy from user recovery Tony Luck
2021-08-20 17:31     ` Borislav Petkov
2021-08-20 18:59       ` Luck, Tony
2021-08-20 19:27         ` Borislav Petkov
2021-08-20 20:23           ` Luck, Tony
2021-08-21  4:51             ` Tony Luck
2021-08-21 21:51               ` Al Viro
2021-08-22 14:36             ` Borislav Petkov
2021-08-20 20:33           ` Luck, Tony
2021-08-22 14:46             ` Borislav Petkov [this message]
2021-08-23 15:24               ` Luck, Tony
2021-09-13  9:24     ` Borislav Petkov
2021-09-13 21:52       ` [PATCH v3] " Luck, Tony
2021-09-14  8:28         ` Borislav Petkov
2021-08-18  0:29   ` [PATCH v2 2/3] x86/mce: Change to not send SIGBUS error during copy from user Tony Luck
2021-09-21  7:52     ` [tip: ras/core] " tip-bot2 for Tony Luck
2021-08-18  0:29   ` [PATCH v2 3/3] x86/mce: Drop copyin special case for #MC Tony Luck
2021-09-20  9:13     ` Borislav Petkov
2021-09-20 16:18       ` Luck, Tony
2021-09-20 16:37         ` Borislav Petkov
2021-09-20 16:43           ` Luck, Tony
2021-09-21  7:52     ` [tip: ras/core] " tip-bot2 for Tony Luck
2021-08-18 16:14   ` [PATCH v2 0/3] More machine check recovery fixes Luck, Tony
  -- strict thread matches above, loose matches on Subject: below --
2021-01-08 22:22 [PATCH 0/2] Fix infinite machine check loop in futex_wait_setup() Tony Luck
2021-01-11 21:44 ` [PATCH v2 0/3] " Tony Luck
2021-01-11 21:44   ` [PATCH v2 1/3] x86/mce: Avoid infinite loop for copy from user recovery Tony Luck
2021-01-11 22:11     ` Andy Lutomirski
2021-01-11 22:20       ` Luck, Tony
2021-01-12 17:00         ` Andy Lutomirski
2021-01-12 17:16           ` Luck, Tony
2021-01-12 17:21             ` Andy Lutomirski
2021-01-12 18:23               ` Luck, Tony
2021-01-12 18:57                 ` Andy Lutomirski
2021-01-12 20:52                   ` Luck, Tony
2021-01-12 22:04                     ` Andy Lutomirski
2021-01-13  1:50                       ` Luck, Tony
2021-01-13  4:15                         ` Andy Lutomirski
2021-01-13 10:00                           ` Borislav Petkov
2021-01-13 16:06                             ` Luck, Tony
2021-01-13 16:19                               ` Borislav Petkov
2021-01-13 16:32                                 ` Luck, Tony
2021-01-13 17:35                                   ` Borislav Petkov
2021-01-14 20:22     ` Borislav Petkov
2021-01-14 21:05       ` Luck, Tony

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