Re: [Bug 1895080] [NEW] pgb_reserved_va: Assertion `addr == test' failed

[Hansni Bu]

No, it's not set by CentOS-7.5.
Does it mean that we just cannot run the ELF in such a case? I've tried
many times, the assert always fails. Maybe, we can blame CentOS-7.5.
BTW: with the option "-p 65536", the case runs successfully.

On Fri, Sep 11, 2020 at 5:50 PM Alex Bennée <1895080@bugs.launchpad.net>
wrote:

> Alex Bennée <alex.bennee@linaro.org> writes:
>
> > Laurent Vivier <laurent@vivier.eu> writes:
> >
> <snip>
> >>> Then trying qemu-riscv32 with a simple ELF, I get:
> >>> linux-user/elfload.c:2341: pgb_reserved_va: Assertion `addr == test'
> failed.
> >>>
> >>> strace shows that:
> >>> mmap(0x1000, 4294963200, PROT_NONE,
> MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, -1, 0) = 0x10000
> >>> write(2, "qemu-riscv32: ../qemu.git/linux-"..., 103qemu-riscv32:
> ../qemu.git/linux-user/elfload.c:2341: pgb_reserved_va: Assertion `addr ==
> test' failed.
> >>> ) = 103
> >>>
> >>> The source code is in the function pgb_reserved_va (linux-
> >>> user/elfload.c). I think mmap cannot guarantee that the returned
> pointer
> >>> (test) equals to the parameter of addr. So is this a bug to assert
> (addr
> >>> == test)?
> >>
> > I'm assuming CentOS 7.5 actually has a definition for
> > MAP_FIXED_NOREPLACE which should ensure we get what we asked for -
> > otherwise we are in the position of hoping the kernel honours what we
> > asked for.
>
> Doh re-reading I see it's not set in the strace output. Maybe we should
> promote the assert case to the failure leg so we have:
>
>     if (addr == MAP_FAILED || addr != test) {
>         error_report(...)
>     }
>
> so we at least fail with a user friendly error rather than an abort?
>
> --
> Alex Bennée
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1895080
>
> Title:
>   pgb_reserved_va: Assertion `addr == test' failed
>
> Status in QEMU:
>   New
>
> Bug description:
>   This problem occurs on CentOS-7.5 (64-bit) with qemu-5.1.0, qemu head
>   (commit 9435a8b3dd35f1f926f1b9127e8a906217a5518a) for riscv32-linux-
>   user.
>
>   Firstly, compile fails:
>   Compiling C object libqemu-riscv32-linux-user.fa.p/linux-user_strace.c.o
>   ../qemu.git/linux-user/strace.c:1210:18: error: ‘FALLOC_FL_KEEP_SIZE’
> undeclared here (not in a function)
>        FLAG_GENERIC(FALLOC_FL_KEEP_SIZE),
>
>   I have to add below include to linux-user/strace.c
>   diff --git a/linux-user/strace.c b/linux-user/strace.c
>   index 11fea14fba..22e51d4a8a 100644
>   --- a/linux-user/strace.c
>   +++ b/linux-user/strace.c
>   @@ -7,6 +7,7 @@
>    #include <sys/mount.h>
>    #include <arpa/inet.h>
>    #include <netinet/tcp.h>
>   +#include <linux/falloc.h>
>    #include <linux/if_packet.h>
>    #include <linux/netlink.h>
>    #include <sched.h>
>
>   Then trying qemu-riscv32 with a simple ELF, I get:
>   linux-user/elfload.c:2341: pgb_reserved_va: Assertion `addr == test'
> failed.
>
>   strace shows that:
>   mmap(0x1000, 4294963200, PROT_NONE,
> MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, -1, 0) = 0x10000
>   write(2, "qemu-riscv32: ../qemu.git/linux-"..., 103qemu-riscv32:
> ../qemu.git/linux-user/elfload.c:2341: pgb_reserved_va: Assertion `addr ==
> test' failed.
>   ) = 103
>
>   The source code is in the function pgb_reserved_va (linux-
>   user/elfload.c). I think mmap cannot guarantee that the returned
>   pointer (test) equals to the parameter of addr. So is this a bug to
>   assert (addr == test)?
>
>   Attached configure script and test ELF file.
>
>   Thanks.
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/qemu/+bug/1895080/+subscriptions
>

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https://bugs.launchpad.net/bugs/1895080

Title:
  pgb_reserved_va: Assertion `addr == test' failed

Status in QEMU:
  New

Bug description:
  This problem occurs on CentOS-7.5 (64-bit) with qemu-5.1.0, qemu head
  (commit 9435a8b3dd35f1f926f1b9127e8a906217a5518a) for riscv32-linux-
  user.

  Firstly, compile fails:
  Compiling C object libqemu-riscv32-linux-user.fa.p/linux-user_strace.c.o
  ../qemu.git/linux-user/strace.c:1210:18: error: ‘FALLOC_FL_KEEP_SIZE’ 
undeclared here (not in a function)
       FLAG_GENERIC(FALLOC_FL_KEEP_SIZE),

  I have to add below include to linux-user/strace.c
  diff --git a/linux-user/strace.c b/linux-user/strace.c
  index 11fea14fba..22e51d4a8a 100644
  --- a/linux-user/strace.c
  +++ b/linux-user/strace.c
  @@ -7,6 +7,7 @@
   #include <sys/mount.h>
   #include <arpa/inet.h>
   #include <netinet/tcp.h>
  +#include <linux/falloc.h>
   #include <linux/if_packet.h>
   #include <linux/netlink.h>
   #include <sched.h>

  Then trying qemu-riscv32 with a simple ELF, I get:
  linux-user/elfload.c:2341: pgb_reserved_va: Assertion `addr == test' failed.

  strace shows that:
  mmap(0x1000, 4294963200, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 
-1, 0) = 0x10000
  write(2, "qemu-riscv32: ../qemu.git/linux-"..., 103qemu-riscv32: 
../qemu.git/linux-user/elfload.c:2341: pgb_reserved_va: Assertion `addr == 
test' failed.
  ) = 103

  The source code is in the function pgb_reserved_va (linux-
  user/elfload.c). I think mmap cannot guarantee that the returned
  pointer (test) equals to the parameter of addr. So is this a bug to
  assert (addr == test)?

  Attached configure script and test ELF file.

  Thanks.

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