On Tue, 2018-02-13 at 11:04 +0100, Michal Hocko wrote: > > From 97e7355a6dc31a73005fa806566a57eb5c38032b Mon Sep 17 00:00:00 > 2001 > From: Michal Hocko <mhocko@xxxxxxxx> > Date: Tue, 13 Feb 2018 10:50:53 +0100 > Subject: [PATCH] elf: enforce MAP_FIXED on overlaying elf segments > > Anshuman has reported that some ELF binaries in his environment fail > to > start with > [ 23.423642] 9148 (sed): Uhuuh, elf segment at 0000000010030000 > requested but the memory is mapped already > [ 23.423706] requested [10030000, 10040000] mapped [10030000, > 10040000] 100073 anon > > The reason is that the above binary has overlapping elf segments: > LOAD 0x0000000000000000 0x0000000010000000 > 0x0000000010000000 > 0x0000000000013a8c 0x0000000000013a8c R E 10000 > LOAD 0x000000000001fd40 0x000000001002fd40 > 0x000000001002fd40 > 0x00000000000002c0 0x00000000000005e8 RW 10000 > LOAD 0x0000000000020328 0x0000000010030328 > 0x0000000010030328 > 0x0000000000000384 0x00000000000094a0 RW 10000 > > That binary has two RW LOAD segments, the first crosses a page border > into the second > > 0x1002fd40 (LOAD2-vaddr) + 0x5e8 (LOAD2-memlen) == 0x10030328 (LOAD3- > vaddr) > > Handle this situation by enforcing MAP_FIXED when we establish a > temporary brk VMA to handle overlapping segments. All other mappings > will still use MAP_FIXED_NOREPLACE. > > Fixes: fs, elf: drop MAP_FIXED usage from elf_map > Reported-by: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx> > Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> > --- > Looks reasonable to me. Reviewed-by: Khalid Aziz <khalid.aziz@xxxxxxxxxx>
