From: Al Viro <viro@zeniv.linux.org.uk>
To: Chen Huang <chenhuang5@huawei.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
"Matthew Wilcox (Oracle)" <willy@infradead.org>,
Randy Dunlap <rdunlap@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
linux-mm <linux-mm@kvack.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [BUG] arm64: an infinite loop in generic_perform_write()
Date: Wed, 23 Jun 2021 02:50:54 +0000 [thread overview]
Message-ID: <YNKhjkuzXEJrBUA8@zeniv-ca.linux.org.uk> (raw)
In-Reply-To: <da9c2fa9-a545-0c48-4490-d6134cc31425@huawei.com>
On Wed, Jun 23, 2021 at 10:39:31AM +0800, Chen Huang wrote:
> Then when kernel handles the alignment_fault, it will not panic. As the
> arm64 memory model spec said, when the address is not a multiple of the
> element size, the access is unaligned. Unaligned accesses are allowed to
> addresses marked as Normal, but not to Device regions. An unaligned access
> to a Device region will trigger an exception (alignment fault).
>
> do_alignment_fault
> do_bad_area
> __do_kernel_fault
> fixup_exception
>
> But that fixup cann't handle the unaligned copy, so the
> copy_page_from_iter_atomic returns 0 and traps in loop.
Looks like you need to fix your raw_copy_from_user(), then...
next prev parent reply other threads:[~2021-06-23 2:51 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-23 2:39 Chen Huang
2021-06-23 2:50 ` Al Viro [this message]
2021-06-23 3:24 ` Xiaoming Ni
2021-06-23 4:27 ` Al Viro
2021-06-23 9:32 ` Catalin Marinas
2021-06-23 11:51 ` Matthew Wilcox
2021-06-23 13:04 ` Al Viro
2021-06-23 13:22 ` Mark Rutland
2021-06-24 3:10 ` Chen Huang
2021-06-24 3:24 ` Matthew Wilcox
2021-06-24 3:52 ` Chen Huang
2021-06-24 7:04 ` Christoph Hellwig
2021-06-24 11:15 ` Matthew Wilcox
2021-06-24 13:22 ` Robin Murphy
2021-06-24 16:27 ` Al Viro
2021-06-24 16:38 ` Robin Murphy
2021-06-24 16:39 ` Al Viro
2021-06-24 17:24 ` Robin Murphy
2021-06-24 18:55 ` Catalin Marinas
2021-06-24 20:36 ` Robin Murphy
2021-06-25 10:39 ` Catalin Marinas
2021-06-28 16:22 ` Robin Murphy
2021-06-29 8:30 ` Catalin Marinas
2021-06-29 10:01 ` Robin Murphy
2021-07-06 17:50 ` Catalin Marinas
2021-07-06 19:15 ` Robin Murphy
2021-07-07 9:55 ` David Laight
2021-07-07 11:04 ` Robin Murphy
2021-07-07 12:50 ` Catalin Marinas
2021-06-24 15:09 ` Catalin Marinas
2021-06-24 16:17 ` Al Viro
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