From: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
To: Eva Kotova <nyandarknessgirl@gmail.com>
Cc: c141028@gmail.com, dramforever@live.com,
linux-riscv@lists.infradead.org, palmer@dabbelt.com,
xc-tan@outlook.com, coelacanthus@outlook.com
Subject: Re: [PATCH] riscv: mmap with PROT_WRITE but no PROT_READ is invalid
Date: Tue, 11 Oct 2022 13:23:10 +0200 [thread overview]
Message-ID: <b0ad936d-4d1b-e319-fa22-4a96c048a855@canonical.com> (raw)
In-Reply-To: <a69ee775-e565-3d72-eb5f-8378616694d3@gmail.com>
On 10/6/22 21:17, Eva Kotova wrote:
> On Tue, 31 May 2022 00:56:52 PDT (-0700), coelacanthus@outlook.com wrote:
> > As mentioned in Table 4.5 in RISC-V spec Volume 2 Section 4.3, write
> > but not read is "Reserved for future use.". For now, they are not valid.
> > In the current code, -wx is marked as invalid, but -w- is not marked
> > as invalid.
>
> This patch breaks OpenJDK/Java on RISC-V, as it tries to create a w-only
> protective page:
>
> #
> # There is insufficient memory for the Java Runtime Environment to
> continue.
> # Native memory allocation (mmap) failed to map 4096 bytes for failed to
> allocate memory for PaX check.
> # An error report file with more information is saved as:
> # /root/hs_err_pid107.log
>
> I bisected to this commit since on Linux 5.19+ java no longer works.
> Perhaps some fallback should be implemented, to prevent userspace
> breakage. It is currently documented, that at least on i386 PROT_WRITE
> mappings imply PROT_READ (See man mmap(2) NOTES), this would be a good
> place to start.
Which test case demonstrates the issue?
Best regards
Heinrich
>
> Best regards,
> Eva
>
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv
>
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next prev parent reply other threads:[~2022-10-11 11:23 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-31 7:56 [PATCH] riscv: mmap with PROT_WRITE but no PROT_READ is invalid Celeste Liu
2022-07-21 23:19 ` Palmer Dabbelt
2022-10-06 19:17 ` Eva Kotova
2022-10-06 19:29 ` Conor Dooley
2022-10-11 11:23 ` Heinrich Schuchardt [this message]
2022-10-11 11:31 ` Coelacanthus
2022-10-06 19:20 ` Eva Kotova
2022-10-06 19:26 ` Conor Dooley
2022-10-06 19:55 ` Eva Kotova
2022-10-06 20:03 ` Conor Dooley
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