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author | Ingo Molnar <mingo@kernel.org> | 2017-11-07 10:53:06 +0100 |
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committer | Ingo Molnar <mingo@kernel.org> | 2017-11-07 10:53:06 +0100 |
commit | b3d9a136815ca9284ade2a897a3b7d2b0084c33c (patch) | |
tree | af222e53d833ff7218577cf98e1b856d9d6bda93 /arch/x86/mm/fault.c | |
parent | c7da092a1f243bfd1bfb4124f538e69e941882da (diff) | |
parent | e4880bc5dfb1f02b152e62a894b5c6f3e995b3cf (diff) | |
download | linux-b3d9a136815ca9284ade2a897a3b7d2b0084c33c.tar.bz2 |
Merge branch 'linus' into x86/asm, to pick up fixes and resolve conflicts
Conflicts:
arch/x86/kernel/cpu/Makefile
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/mm/fault.c')
-rw-r--r-- | arch/x86/mm/fault.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index db71c73530bd..3109ba6c6ede 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 1995 Linus Torvalds * Copyright (C) 2001, 2002 Andi Kleen, SuSE Labs. @@ -1420,7 +1421,17 @@ good_area: * make sure we exit gracefully rather than endlessly redo * the fault. Since we never set FAULT_FLAG_RETRY_NOWAIT, if * we get VM_FAULT_RETRY back, the mmap_sem has been unlocked. + * + * Note that handle_userfault() may also release and reacquire mmap_sem + * (and not return with VM_FAULT_RETRY), when returning to userland to + * repeat the page fault later with a VM_FAULT_NOPAGE retval + * (potentially after handling any pending signal during the return to + * userland). The return to userland is identified whenever + * FAULT_FLAG_USER|FAULT_FLAG_KILLABLE are both set in flags. + * Thus we have to be careful about not touching vma after handling the + * fault, so we read the pkey beforehand. */ + pkey = vma_pkey(vma); fault = handle_mm_fault(vma, address, flags); major |= fault & VM_FAULT_MAJOR; @@ -1447,7 +1458,6 @@ good_area: return; } - pkey = vma_pkey(vma); up_read(&mm->mmap_sem); if (unlikely(fault & VM_FAULT_ERROR)) { mm_fault_error(regs, error_code, address, &pkey, fault); |