[v2,0/5] linux-user: brk() syscall fixes and armhf static binary fix

Message

Helge Deller July 18, 2023, 6:52 p.m. UTC

Commit 86f04735ac ("linux-user: Fix brk() to release pages") introduced
the possibility for userspace applications to reduce memory footprint by
calling brk() with a lower address and as such free up memory, the same
way as the Linux kernel allows on physical machines.

This change introduced some failures for applications with errors like
- accesing bytes above the brk heap address on the same page,
- freeing memory below the initial brk address,
and introduced a behaviour which isn't done by the kernel (e.g. zeroing
memory above brk).

This patch series fixes those issues and has been tested with existing
programs (e.g. upx).

Additionally one patch fixes running static armhf executables (e.g. fstype)
which was broken since qemu-8.0.

Changes in v2:
- dropped patch to revert d28b3c90cfad ("linux-user: Make sure initial brk(0)
  is page-aligned")
- rephrased some commit messages
- fixed Cc email addresses, added new ones
- added R-b tags

Helge

Helge Deller (5):
  linux-user: Fix qemu brk() to not zero bytes on current page
  linux-user: Prohibit brk() to to shrink below initial heap address
  linux-user: Fix signed math overflow in brk() syscall
  linux-user: Fix strace output for old_mmap
  linux-user: Fix qemu-arm to run static armhf binaries

 linux-user/elfload.c |  7 +++++++
 linux-user/strace.c  | 49 ++++++++++++++++++++++++++++++++++++++++----
 linux-user/syscall.c | 23 +++++++++++++--------
 3 files changed, 66 insertions(+), 13 deletions(-)

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2.41.0