Re: [PATCH 3/3] kvm/eventfd: Drain events from eventfd in irqfd_wakeup()

From: kernel test robot
Date: Tue Oct 27 2020 - 17:43:31 EST


Hi David,

I love your patch! Yet something to improve:

[auto build test ERROR on vfio/next]
[also build test ERROR on vhost/linux-next linus/master kvm/linux-next v5.10-rc1 next-20201027]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url: https://github.com/0day-ci/linux/commits/David-Woodhouse/Allow-in-kernel-consumers-to-drain-events-from-eventfd/20201027-215658
base: https://github.com/awilliam/linux-vfio.git next
config: s390-randconfig-r023-20201027 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project f2c25c70791de95d2466e09b5b58fc37f6ccd7a4)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install s390 cross compiling tool for clang build
# apt-get install binutils-s390x-linux-gnu
# https://github.com/0day-ci/linux/commit/dc45dd9af28fede8f8dd29b705b90f78cf87538c
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review David-Woodhouse/Allow-in-kernel-consumers-to-drain-events-from-eventfd/20201027-215658
git checkout dc45dd9af28fede8f8dd29b705b90f78cf87538c
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=s390

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All errors (new ones prefixed by >>):

In file included from arch/s390/include/asm/kvm_para.h:25:
In file included from arch/s390/include/asm/diag.h:12:
In file included from include/linux/if_ether.h:19:
In file included from include/linux/skbuff.h:31:
In file included from include/linux/dma-mapping.h:11:
In file included from include/linux/scatterlist.h:9:
In file included from arch/s390/include/asm/io.h:72:
include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
~~~~~~~~~~ ^
include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu'
#define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
^
include/uapi/linux/swab.h:119:21: note: expanded from macro '__swab32'
___constant_swab32(x) : \
^
include/uapi/linux/swab.h:21:12: note: expanded from macro '___constant_swab32'
(((__u32)(x) & (__u32)0x00ff0000UL) >> 8) | \
^
In file included from arch/s390/kvm/../../../virt/kvm/eventfd.c:12:
In file included from include/linux/kvm_host.h:32:
In file included from include/linux/kvm_para.h:5:
In file included from include/uapi/linux/kvm_para.h:36:
In file included from arch/s390/include/asm/kvm_para.h:25:
In file included from arch/s390/include/asm/diag.h:12:
In file included from include/linux/if_ether.h:19:
In file included from include/linux/skbuff.h:31:
In file included from include/linux/dma-mapping.h:11:
In file included from include/linux/scatterlist.h:9:
In file included from arch/s390/include/asm/io.h:72:
include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
~~~~~~~~~~ ^
include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu'
#define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
^
include/uapi/linux/swab.h:119:21: note: expanded from macro '__swab32'
___constant_swab32(x) : \
^
include/uapi/linux/swab.h:22:12: note: expanded from macro '___constant_swab32'
(((__u32)(x) & (__u32)0xff000000UL) >> 24)))
^
In file included from arch/s390/kvm/../../../virt/kvm/eventfd.c:12:
In file included from include/linux/kvm_host.h:32:
In file included from include/linux/kvm_para.h:5:
In file included from include/uapi/linux/kvm_para.h:36:
In file included from arch/s390/include/asm/kvm_para.h:25:
In file included from arch/s390/include/asm/diag.h:12:
In file included from include/linux/if_ether.h:19:
In file included from include/linux/skbuff.h:31:
In file included from include/linux/dma-mapping.h:11:
In file included from include/linux/scatterlist.h:9:
In file included from arch/s390/include/asm/io.h:72:
include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
~~~~~~~~~~ ^
include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu'
#define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
^
include/uapi/linux/swab.h:120:12: note: expanded from macro '__swab32'
__fswab32(x))
^
In file included from arch/s390/kvm/../../../virt/kvm/eventfd.c:12:
In file included from include/linux/kvm_host.h:32:
In file included from include/linux/kvm_para.h:5:
In file included from include/uapi/linux/kvm_para.h:36:
In file included from arch/s390/include/asm/kvm_para.h:25:
In file included from arch/s390/include/asm/diag.h:12:
In file included from include/linux/if_ether.h:19:
In file included from include/linux/skbuff.h:31:
In file included from include/linux/dma-mapping.h:11:
In file included from include/linux/scatterlist.h:9:
In file included from arch/s390/include/asm/io.h:72:
include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writeb(value, PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:511:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:521:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:609:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
readsb(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:617:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
readsw(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:625:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
readsl(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:634:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
writesb(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:643:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
writesw(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:652:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
writesl(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
>> arch/s390/kvm/../../../virt/kvm/eventfd.c:197:23: error: incompatible pointer types passing 'struct eventfd_ctx **' to parameter of type 'struct eventfd_ctx *'; remove & [-Werror,-Wincompatible-pointer-types]
eventfd_ctx_do_read(&irqfd->eventfd, &cnt);
^~~~~~~~~~~~~~~
include/linux/eventfd.h:44:46: note: passing argument to parameter 'ctx' here
void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt);
^
20 warnings and 1 error generated.

vim +197 arch/s390/kvm/../../../virt/kvm/eventfd.c

180
181 /*
182 * Called with wqh->lock held and interrupts disabled
183 */
184 static int
185 irqfd_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
186 {
187 struct kvm_kernel_irqfd *irqfd =
188 container_of(wait, struct kvm_kernel_irqfd, wait);
189 __poll_t flags = key_to_poll(key);
190 struct kvm_kernel_irq_routing_entry irq;
191 struct kvm *kvm = irqfd->kvm;
192 unsigned seq;
193 int idx;
194
195 if (flags & EPOLLIN) {
196 u64 cnt;
> 197 eventfd_ctx_do_read(&irqfd->eventfd, &cnt);
198
199 idx = srcu_read_lock(&kvm->irq_srcu);
200 do {
201 seq = read_seqcount_begin(&irqfd->irq_entry_sc);
202 irq = irqfd->irq_entry;
203 } while (read_seqcount_retry(&irqfd->irq_entry_sc, seq));
204 /* An event has been signaled, inject an interrupt */
205 if (kvm_arch_set_irq_inatomic(&irq, kvm,
206 KVM_USERSPACE_IRQ_SOURCE_ID, 1,
207 false) == -EWOULDBLOCK)
208 schedule_work(&irqfd->inject);
209 srcu_read_unlock(&kvm->irq_srcu, idx);
210 }
211
212 if (flags & EPOLLHUP) {
213 /* The eventfd is closing, detach from KVM */
214 unsigned long iflags;
215
216 spin_lock_irqsave(&kvm->irqfds.lock, iflags);
217
218 /*
219 * We must check if someone deactivated the irqfd before
220 * we could acquire the irqfds.lock since the item is
221 * deactivated from the KVM side before it is unhooked from
222 * the wait-queue. If it is already deactivated, we can
223 * simply return knowing the other side will cleanup for us.
224 * We cannot race against the irqfd going away since the
225 * other side is required to acquire wqh->lock, which we hold
226 */
227 if (irqfd_is_active(irqfd))
228 irqfd_deactivate(irqfd);
229
230 spin_unlock_irqrestore(&kvm->irqfds.lock, iflags);
231 }
232
233 return 0;
234 }
235

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx

Attachment: .config.gz
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