linux-dev/arch/um, branch linus/master

um: virt-pci: set device ready in probe()

2022-06-11T00:38:06Z

Call virtio_device_ready() to make this driver work after commit b4ec69d7e09 ("virtio: harden vring IRQ"), since the driver uses the virtqueues in the probe function. (The virtio core sets the device ready when probe returns.) Fixes: 8b4ec69d7e09 ("virtio: harden vring IRQ") Fixes: 68f5d3f3b654 ("um: add PCI over virtio emulation driver") Signed-off-by: Vincent Whitchurch Message-Id: <20220610151203.3492541-1-vincent.whitchurch@axis.com> Signed-off-by: Michael S. Tsirkin Tested-by: Johannes Berg

Merge tag 'ptrace_stop-cleanup-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2022-06-03T23:13:25Z

Pull ptrace_stop cleanups from Eric Biederman: "While looking at the ptrace problems with PREEMPT_RT and the problems Peter Zijlstra was encountering with ptrace in his freezer rewrite I identified some cleanups to ptrace_stop that make sense on their own and move make resolving the other problems much simpler. The biggest issue is the habit of the ptrace code to change task->__state from the tracer to suppress TASK_WAKEKILL from waking up the tracee. No other code in the kernel does that and it is straight forward to update signal_wake_up and friends to make that unnecessary. Peter's task freezer sets frozen tasks to a new state TASK_FROZEN and then it stores them by calling "wake_up_state(t, TASK_FROZEN)" relying on the fact that all stopped states except the special stop states can tolerate spurious wake up and recover their state. The state of stopped and traced tasked is changed to be stored in task->jobctl as well as in task->__state. This makes it possible for the freezer to recover tasks in these special states, as well as serving as a general cleanup. With a little more work in that direction I believe TASK_STOPPED can learn to tolerate spurious wake ups and become an ordinary stop state. The TASK_TRACED state has to remain a special state as the registers for a process are only reliably available when the process is stopped in the scheduler. Fundamentally ptrace needs acess to the saved register values of a task. There are bunch of semi-random ptrace related cleanups that were found while looking at these issues. One cleanup that deserves to be called out is from commit 57b6de08b5f6 ("ptrace: Admit ptrace_stop can generate spuriuos SIGTRAPs"). This makes a change that is technically user space visible, in the handling of what happens to a tracee when a tracer dies unexpectedly. According to our testing and our understanding of userspace nothing cares that spurious SIGTRAPs can be generated in that case" * tag 'ptrace_stop-cleanup-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: sched,signal,ptrace: Rework TASK_TRACED, TASK_STOPPED state ptrace: Always take siglock in ptrace_resume ptrace: Don't change __state ptrace: Admit ptrace_stop can generate spuriuos SIGTRAPs ptrace: Document that wait_task_inactive can't fail ptrace: Reimplement PTRACE_KILL by always sending SIGKILL signal: Use lockdep_assert_held instead of assert_spin_locked ptrace: Remove arch_ptrace_attach ptrace/xtensa: Replace PT_SINGLESTEP with TIF_SINGLESTEP ptrace/um: Replace PT_DTRACE with TIF_SINGLESTEP signal: Replace __group_send_sig_info with send_signal_locked signal: Rename send_signal send_signal_locked

Merge tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2022-06-03T23:03:05Z

Pull kthread updates from Eric Biederman: "This updates init and user mode helper tasks to be ordinary user mode tasks. Commit 40966e316f86 ("kthread: Ensure struct kthread is present for all kthreads") caused init and the user mode helper threads that call kernel_execve to have struct kthread allocated for them. This struct kthread going away during execve in turned made a use after free of struct kthread possible. Here, commit 343f4c49f243 ("kthread: Don't allocate kthread_struct for init and umh") is enough to fix the use after free and is simple enough to be backportable. The rest of the changes pass struct kernel_clone_args to clean things up and cause the code to make sense. In making init and the user mode helpers tasks purely user mode tasks I ran into two complications. The function task_tick_numa was detecting tasks without an mm by testing for the presence of PF_KTHREAD. The initramfs code in populate_initrd_image was using flush_delayed_fput to ensuere the closing of all it's file descriptors was complete, and flush_delayed_fput does not work in a userspace thread. I have looked and looked and more complications and in my code review I have not found any, and neither has anyone else with the code sitting in linux-next" * tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: sched: Update task_tick_numa to ignore tasks without an mm fork: Stop allowing kthreads to call execve fork: Explicitly set PF_KTHREAD init: Deal with the init process being a user mode process fork: Generalize PF_IO_WORKER handling fork: Explicity test for idle tasks in copy_thread fork: Pass struct kernel_clone_args into copy_thread kthread: Don't allocate kthread_struct for init and umh

Merge tag 'for-linus-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml

2022-06-03T21:35:14Z

Pull UML updates from Richard Weinberger: - Various cleanups and fixes: xterm, serial line, time travel - Set ARCH_HAS_GCOV_PROFILE_ALL * tag 'for-linus-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml: um: Fix out-of-bounds read in LDT setup um: chan_user: Fix winch_tramp() return value um: virtio_uml: Fix broken device handling in time-travel um: line: Use separate IRQs per line um: Enable ARCH_HAS_GCOV_PROFILE_ALL um: Use asm-generic/dma-mapping.h um: daemon: Make default socket configurable um: xterm: Make default terminal emulator configurable

um: chan_user: Fix winch_tramp() return value

2022-05-27T07:03:41Z

The previous fix here was only partially correct, it did result in returning a proper error value in case of error, but it also clobbered the pid that we need to return from this function (not just zero for success). As a result, it returned 0 here, but later this is treated as a pid and used to kill the process, but since it's now 0 we kill(0, SIGKILL), which makes UML kill itself rather than just the helper thread. Fix that and make it more obvious by using a separate variable for the pid. Fixes: ccf1236ecac4 ("um: fix error return code in winch_tramp()") Reported-and-tested-by: Nathan Chancellor Signed-off-by: Johannes Berg Cc: stable@vger.kernel.org Signed-off-by: Richard Weinberger

um: virtio_uml: Fix broken device handling in time-travel

2022-05-27T07:03:41Z

If a device implementation crashes, virtio_uml will mark it as dead by calling virtio_break_device() and scheduling the work that will remove it. This still seems like the right thing to do, but it's done directly while reading the message, and if time-travel is used, this is in the time-travel handler, outside of the normal Linux machinery. Therefore, we cannot acquire locks or do normal "linux-y" things because e.g. lockdep will be confused about the context. Move handling this situation out of the read function and into the actual IRQ handler and response handling instead, so that in the case of time-travel we don't call it in the wrong context. Chances are the system will still crash immediately, since the device implementation crashing may also cause the time- travel controller to go down, but at least all of that now happens without strange warnings from lockdep. Fixes: c8177aba37ca ("um: time-travel: rework interrupt handling in ext mode") Cc: stable@vger.kernel.org Signed-off-by: Johannes Berg Signed-off-by: Richard Weinberger

um: line: Use separate IRQs per line

2022-05-27T07:03:41Z

Today, all possible serial lines (ssl*=) as well as all possible consoles (con*=) each share a single interrupt (with a fixed number) with others of the same type. Now, if you have two lines, say ssl0 and ssl1, and one of them is connected to an fd you cannot read (e.g. a file), but the other gets a read interrupt, then both of them get the interrupt since it's shared. Then, the read() call will return EOF, since it's a file being written and there's nothing to read (at least not at the current offset, at the end). Unfortunately, this is treated as a read error, and we close this line, losing all the possible output. It might be possible to work around this and make the IRQ sharing work, however, now that we have dynamically allocated IRQs that are easy to use, simply use that to achieve separating between the events; then there's no interrupt for that line and we never attempt the read in the first place, thus not closing the line. This manifested itself in the wifi hostap/hwsim tests where the parallel script communicates via one serial console and the kernel messages go to another (a file) and sending data on the communication console caused the kernel messages to stop flowing into the file. Reported-by: Jouni Malinen Signed-off-by: Johannes Berg Acked-By: anton ivanov Signed-off-by: Richard Weinberger

um: Enable ARCH_HAS_GCOV_PROFILE_ALL

2022-05-27T07:01:14Z

Enable ARCH_HAS_GCOV_PROFILE_ALL so that CONFIG_GCOV_PROFILE_ALL can be selected on UML. I didn't need to explicitly disable GCOV on anything to get this to work on the configs I tested. Signed-off-by: Vincent Whitchurch Signed-off-by: Richard Weinberger

um: Use asm-generic/dma-mapping.h

2022-05-27T07:00:45Z

If DMA (PCI over virtio) is enabled, then some drivers may enable CONFIG_DMA_OPS as well, and then we pull in the x86 definition of get_arch_dma_ops(), which uses the dma_ops symbol, which isn't defined. Since we don't have real DMA ops nor any kind of IOMMU fix this in the simplest possible way: pull in the asm-generic file instead of inheriting the x86 one. It's not clear why those drivers that do (e.g. VDPA) "select DMA_OPS", and if they'd even work with this, but chances are nobody will be wanting to do that anyway, so fixing the build failure is good enough. Reported-by: Randy Dunlap Fixes: 68f5d3f3b654 ("um: add PCI over virtio emulation driver") Signed-off-by: Johannes Berg Tested-by: Randy Dunlap Acked-by: Randy Dunlap Cc: stable@vger.kernel.org Signed-off-by: Richard Weinberger

um: daemon: Make default socket configurable

2022-05-27T07:00:40Z

Even if daemon network is deprecated, some configurations may still use it (e.g. Debian), and not want to default to the /tmp/uml.ctl socket location. Allow configuring the default socket location. Signed-off-by: Johannes Berg Acked-By: Anton Ivanov Tested-by: Ritesh Raj Sarraf Signed-off-by: Richard Weinberger