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Groups > linux.kernel > #1574259
| From | Willy Tarreau <w@1wt.eu> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 3.10 036/319] xen-blkback: only read request operation from shared ring once |
| Date | 2017-02-05 21:30 +0100 |
| Message-ID | <t7BBF-3FO-45@gated-at.bofh.it> (permalink) |
| References | <t7AFA-32I-9@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
From: Roger Pau Monné <roger.pau@citrix.com>
commit 1f13d75ccb806260079e0679d55d9253e370ec8a upstream.
A compiler may load a switch statement value multiple times, which could
be bad when the value is in memory shared with the frontend.
When converting a non-native request to a native one, ensure that
src->operation is only loaded once by using READ_ONCE().
This is part of XSA155.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: "Jan Beulich" <JBeulich@suse.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
drivers/block/xen-blkback/common.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h
index 60103e2..6774cba 100644
--- a/drivers/block/xen-blkback/common.h
+++ b/drivers/block/xen-blkback/common.h
@@ -269,8 +269,8 @@ static inline void blkif_get_x86_32_req(struct blkif_request *dst,
struct blkif_x86_32_request *src)
{
int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
- dst->operation = src->operation;
- switch (src->operation) {
+ dst->operation = READ_ONCE(src->operation);
+ switch (dst->operation) {
case BLKIF_OP_READ:
case BLKIF_OP_WRITE:
case BLKIF_OP_WRITE_BARRIER:
@@ -305,8 +305,8 @@ static inline void blkif_get_x86_64_req(struct blkif_request *dst,
struct blkif_x86_64_request *src)
{
int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
- dst->operation = src->operation;
- switch (src->operation) {
+ dst->operation = READ_ONCE(src->operation);
+ switch (dst->operation) {
case BLKIF_OP_READ:
case BLKIF_OP_WRITE:
case BLKIF_OP_WRITE_BARRIER:
--
2.8.0.rc2.1.gbe9624a
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[PATCH 3.10 030/319] PM / devfreq: Fix incorrect type issue. Willy Tarreau <w@1wt.eu> - 2017-02-05 20:30 +0100
[PATCH 3.10 067/319] powerpc/64: Fix incorrect return value from __copy_tofrom_user Willy Tarreau <w@1wt.eu> - 2017-02-05 20:30 +0100
[PATCH 3.10 040/319] xen/pciback: Do not install an IRQ handler for MSI interrupts. Willy Tarreau <w@1wt.eu> - 2017-02-05 20:30 +0100
[PATCH 3.10 079/319] score: fix __get_user/get_user Willy Tarreau <w@1wt.eu> - 2017-02-05 20:30 +0100
[PATCH 3.10 095/319] openrisc: fix the fix of copy_from_user() Willy Tarreau <w@1wt.eu> - 2017-02-05 20:30 +0100
[PATCH 3.10 086/319] score: fix copy_from_user() and friends Willy Tarreau <w@1wt.eu> - 2017-02-05 20:30 +0100
[PATCH 3.10 072/319] s390/dasd: fix hanging device after clear subchannel Willy Tarreau <w@1wt.eu> - 2017-02-05 20:30 +0100
[PATCH 3.10 060/319] arm64: spinlocks: implement smp_mb__before_spinlock() as smp_mb() Willy Tarreau <w@1wt.eu> - 2017-02-05 20:40 +0100
[PATCH 3.10 093/319] parisc: fix copy_from_user() Willy Tarreau <w@1wt.eu> - 2017-02-05 20:40 +0100
[PATCH 3.10 087/319] sh: fix copy_from_user() Willy Tarreau <w@1wt.eu> - 2017-02-05 20:40 +0100
[PATCH 3.10 094/319] openrisc: fix copy_from_user() Willy Tarreau <w@1wt.eu> - 2017-02-05 20:40 +0100
[PATCH 3.10 063/319] MIPS: ptrace: Fix regs_return_value for kernel context Willy Tarreau <w@1wt.eu> - 2017-02-05 20:50 +0100
[PATCH 3.10 059/319] arm64: Define AT_VECTOR_SIZE_ARCH for ARCH_DLINFO Willy Tarreau <w@1wt.eu> - 2017-02-05 20:50 +0100
[PATCH 3.10 055/319] ARM: 8618/1: decompressor: reset ttbcr fields to use TTBR0 on ARMv7 Willy Tarreau <w@1wt.eu> - 2017-02-05 20:50 +0100
[PATCH 3.10 034/319] xen-netback: don't use last request to determine minimum Tx credit Willy Tarreau <w@1wt.eu> - 2017-02-05 21:00 +0100
[PATCH 3.10 091/319] alpha: fix copy_from_user() Willy Tarreau <w@1wt.eu> - 2017-02-05 21:00 +0100
[PATCH 3.10 076/319] mn10300: failing __get_user() and get_user() should zero Willy Tarreau <w@1wt.eu> - 2017-02-05 21:10 +0100
[PATCH 3.10 070/319] avr32: fix 'undefined reference to `___copy_from_user' Willy Tarreau <w@1wt.eu> - 2017-02-05 21:10 +0100
[PATCH 3.10 049/319] x86/paravirt: Do not trace _paravirt_ident_*() functions Willy Tarreau <w@1wt.eu> - 2017-02-05 21:10 +0100
[PATCH 3.10 068/319] powerpc/nvram: Fix an incorrect partition merge Willy Tarreau <w@1wt.eu> - 2017-02-05 21:10 +0100
[PATCH 3.10 075/319] microblaze: fix copy_from_user() Willy Tarreau <w@1wt.eu> - 2017-02-05 21:10 +0100
[PATCH 3.10 041/319] xen/pciback: For XEN_PCI_OP_disable_msi[|x] only disable if device has MSI(X) enabled. Willy Tarreau <w@1wt.eu> - 2017-02-05 21:20 +0100
[PATCH 3.10 085/319] blackfin: fix copy_from_user() Willy Tarreau <w@1wt.eu> - 2017-02-05 21:20 +0100
[PATCH 3.10 046/319] x86/mm: Disable preemption during CR3 read+write Willy Tarreau <w@1wt.eu> - 2017-02-05 21:20 +0100
[PATCH 3.10 048/319] x86/mm/pat, /dev/mem: Remove superfluous error message Willy Tarreau <w@1wt.eu> - 2017-02-05 21:20 +0100
[PATCH 3.10 081/319] ARC: uaccess: get_user to zero out dest in cause of fault Willy Tarreau <w@1wt.eu> - 2017-02-05 21:20 +0100
[PATCH 3.10 037/319] xen/pciback: Save xen_pci_op commands before processing it Willy Tarreau <w@1wt.eu> - 2017-02-05 21:20 +0100
Re: [PATCH 3.10 037/319] xen/pciback: Save xen_pci_op commands before processing it Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> - 2017-02-06 15:40 +0100
Re: [PATCH 3.10 037/319] xen/pciback: Save xen_pci_op commands before processing it Willy Tarreau <w@1wt.eu> - 2017-02-06 23:40 +0100
[PATCH 3.10 050/319] x86/build: Build compressed x86 kernels as PIE Willy Tarreau <w@1wt.eu> - 2017-02-05 21:20 +0100
[PATCH 3.10 057/319] ARM: sa1111: fix pcmcia suspend/resume Willy Tarreau <w@1wt.eu> - 2017-02-05 21:20 +0100
[PATCH 3.10 032/319] x86/mm/xen: Suppress hugetlbfs in PV guests Willy Tarreau <w@1wt.eu> - 2017-02-05 21:20 +0100
[PATCH 3.10 098/319] ppc32: fix copy_from_user() Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 053/319] iommu/amd: Free domain id when free a domain of struct dma_ops_domain Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 099/319] ia64: copy_from_user() should zero the destination on access_ok() failure Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 092/319] metag: copy_from_user() should zero the destination on access_ok() failure Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 047/319] x86/apic: Do not init irq remapping if ioapic is disabled Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 066/319] powerpc/powernv: Use CPU-endian PEST in pnv_pci_dump_p7ioc_diag_data() Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 058/319] arm64: avoid returning from bad_mode Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 065/319] powerpc/vdso64: Use double word compare on pointers Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 031/319] ppp: defer netns reference release for ppp channel Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 064/319] powerpc/mm: Don't alias user region to other regions below PAGE_OFFSET Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 035/319] xen-netback: use RING_COPY_REQUEST() throughout Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 062/319] MIPS: Malta: Fix IOCU disable switch read for MIPS64 Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 033/319] xen: Add RING_COPY_REQUEST() Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 078/319] sh64: failing __get_user() should zero Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 089/319] mips: copy_from_user() must zero the destination on access_ok() failure Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 036/319] xen-blkback: only read request operation from shared ring once Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 083/319] frv: fix clear_user() Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 080/319] s390: get_user() should zero on failure Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 073/319] parisc: Ensure consistent state when switching to kernel stack at syscall entry Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 038/319] xen/pciback: Return error on XEN_PCI_OP_enable_msi when device has MSI or MSI-X enabled Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 054/319] ARM: 8616/1: dt: Respect property size when parsing CPUs Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 088/319] hexagon: fix strncpy_from_user() error return Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 052/319] iommu/amd: Update Alias-DTE in update_device_table() Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 039/319] xen/pciback: Return error on XEN_PCI_OP_enable_msix when device has MSI or MSI-X enabled Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 090/319] asm-generic: make copy_from_user() zero the destination properly Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 044/319] x86/xen: fix upper bound of pmd loop in xen_cleanhighmap() Willy Tarreau <w@1wt.eu> - 2017-02-05 21:30 +0100
[PATCH 3.10 045/319] x86/traps: Ignore high word of regs->cs in early_idt_handler_common Willy Tarreau <w@1wt.eu> - 2017-02-05 21:40 +0100
[PATCH 3.10 042/319] xen/pciback: Don't allow MSI-X ops if PCI_COMMAND_MEMORY is not set. Willy Tarreau <w@1wt.eu> - 2017-02-05 21:40 +0100
[PATCH 3.10 061/319] arm64: debug: avoid resetting stepping state machine when TIF_SINGLESTEP Willy Tarreau <w@1wt.eu> - 2017-02-05 21:40 +0100
[PATCH 3.10 097/319] sparc32: fix copy_from_user() Willy Tarreau <w@1wt.eu> - 2017-02-05 21:40 +0100
[PATCH 3.10 051/319] x86/um: reuse asm-generic/barrier.h Willy Tarreau <w@1wt.eu> - 2017-02-05 21:40 +0100
[PATCH 3.10 043/319] xen-pciback: Add name prefix to global 'permissive' variable Willy Tarreau <w@1wt.eu> - 2017-02-05 21:40 +0100
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