go
/
gvisor
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Ensure all uses of MM.brk occur under MM.mappingMu in MM.Brk(). 

PiperOrigin-RevId: 246921386
Change-Id: I71d8908858f45a9a33a0483470d0240eaf0fd012
This commit is contained in:
Jamie Liu 2019-05-06 16:38:37 -07:00 committed by Shentubot
parent ff8ed5e6a5
commit 14f0e7618e
1 changed files with 14 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
pkg/sentry/mm/syscalls.go
View File

@ -694,8 +694,9 @@ func (mm *MemoryManager) Brk(ctx context.Context, addr usermem.Addr) (usermem.Ad
// Can't defer mm.mappingMu.Unlock(); see below.
if addr < mm.brk.Start {
addr = mm.brk.End
mm.mappingMu.Unlock()
return mm.brk.End, syserror.EINVAL
return addr, syserror.EINVAL
}
// TODO(gvisor.dev/issue/156): This enforces RLIMIT_DATA, but is
@ -704,22 +705,20 @@ func (mm *MemoryManager) Brk(ctx context.Context, addr usermem.Addr) (usermem.Ad
// size of heap + data + bss. The segment sizes need to be plumbed from
// the loader package to fully enforce RLIMIT_DATA.
if uint64(addr-mm.brk.Start) > limits.FromContext(ctx).Get(limits.Data).Cur {
addr = mm.brk.End
mm.mappingMu.Unlock()
return mm.brk.End, syserror.ENOMEM
return addr, syserror.ENOMEM
}
oldbrkpg, _ := mm.brk.End.RoundUp()
newbrkpg, ok := addr.RoundUp()
if !ok {
addr = mm.brk.End
mm.mappingMu.Unlock()
return mm.brk.End, syserror.EFAULT
return addr, syserror.EFAULT
}
switch {
case newbrkpg < oldbrkpg:
mm.unmapLocked(ctx, usermem.AddrRange{newbrkpg, oldbrkpg})
mm.mappingMu.Unlock()
case oldbrkpg < newbrkpg:
vseg, ar, err := mm.createVMALocked(ctx, memmap.MMapOpts{
Length: uint64(newbrkpg - oldbrkpg),
@ -736,21 +735,26 @@ func (mm *MemoryManager) Brk(ctx context.Context, addr usermem.Addr) (usermem.Ad
Hint: "[heap]",
})
if err != nil {
addr = mm.brk.End
mm.mappingMu.Unlock()
return mm.brk.End, err
return addr, err
}
mm.brk.End = addr
if mm.defMLockMode == memmap.MLockEager {
mm.populateVMAAndUnlock(ctx, vseg, ar, true)
} else {
mm.mappingMu.Unlock()
}
case newbrkpg < oldbrkpg:
mm.unmapLocked(ctx, usermem.AddrRange{newbrkpg, oldbrkpg})
fallthrough
default:
// Nothing to do.
mm.brk.End = addr
mm.mappingMu.Unlock()
}
mm.brk.End = addr
return addr, nil
}