diff options
Diffstat (limited to 'vmmon.patch')
| -rw-r--r-- | vmmon.patch | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/vmmon.patch b/vmmon.patch index 6c6c3580c31b..39ffa227bcc4 100644 --- a/vmmon.patch +++ b/vmmon.patch @@ -411,3 +411,99 @@ printk(KERN_ERR "%s: Couldn't verify write to uva 0x%p with size %" FMTSZ"u\n", __func__, p, size); +From 9fda02bce13527ce94a95df1a98fb6188dea22b8 Mon Sep 17 00:00:00 2001 +From: Michal Kubecek <mkubecek@suse.cz> +Date: Wed, 30 Jun 2021 11:05:16 +0200 +Subject: [PATCH] vmmon: fix task_struct::state access patterns + +Mainline commit 2f064a59a11f ("sched: Change task_struct::state") in +5.14-rc1 finishes a series fixing racy access patterns to task state and +renames task_struct::state to __state so that code old code acessing it +directly fails to build. + +Two of these in HostIF_SemaphoreWait() can be rewritten into calls to +set_current_state() unconditionally (second one may do with +__set_current_state() but I don't feel confident enough about that). +There are also two places where vmmon code reads task_struct::state; +provide a compat accessor using READ_ONCE() and use it instead of +a direct read. To avoid kernel version check, check presence of +get_current_state() macro introduced in the same commit as state member +rename. +--- + vmmon-only/include/compat_sched.h | 15 +++++++++++++++ + vmmon-only/linux/hostif.c | 10 ++++++---- + 2 files changed, 21 insertions(+), 4 deletions(-) + +diff --git a/vmmon-only/include/compat_sched.h b/vmmon-only/include/compat_sched.h +index 3f3304b..72078e0 100644 +--- a/vmmon-only/include/compat_sched.h ++++ b/vmmon-only/include/compat_sched.h +@@ -289,5 +289,20 @@ typedef struct pid * compat_pid; + #define compat_kill_pid(pid, sig, flag) kill_pid(pid, sig, flag) + #endif + ++/* ++ * Since v5.14-rc1, task_struct::state hase been renamed to __state and is ++ * is longer supposed to be accessed without READ_ONCE/WRITE_ONCE. ++ */ ++#ifdef get_current_state ++static inline int compat_get_task_state(const struct task_struct *t) ++{ ++ return READ_ONCE(t->__state); ++} ++#else ++static inline int compat_get_task_state(const struct task_struct *t) ++{ ++ return READ_ONCE(t->state); ++} ++#endif + + #endif /* __COMPAT_SCHED_H__ */ +diff --git a/vmmon-only/linux/hostif.c b/vmmon-only/linux/hostif.c +index 137062c..6910f69 100644 +--- a/vmmon-only/linux/hostif.c ++++ b/vmmon-only/linux/hostif.c +@@ -78,6 +78,8 @@ + #include "pgtbl.h" + #include "versioned_atomic.h" + ++#include "compat_sched.h" ++ + #if !defined(CONFIG_HIGH_RES_TIMERS) + #error CONFIG_HIGH_RES_TIMERS required for acceptable performance + #endif +@@ -445,7 +447,7 @@ HostIF_WakeUpYielders(VMDriver *vm, // IN: + while ((vcpuid = VCPUSet_FindFirst(&req)) != VCPUID_INVALID) { + struct task_struct *t = vm->vmhost->vcpuSemaTask[vcpuid]; + VCPUSet_Remove(&req, vcpuid); +- if (t && (t->state & TASK_INTERRUPTIBLE)) { ++ if (t && (compat_get_task_state(t) & TASK_INTERRUPTIBLE)) { + wake_up_process(t); + } + } +@@ -2454,14 +2456,14 @@ HostIF_SemaphoreWait(VMDriver *vm, // IN: + unsigned int mask; + + poll_initwait(&table); +- current->state = TASK_INTERRUPTIBLE; ++ set_current_state(TASK_INTERRUPTIBLE); + mask = file->f_op->poll(file, &table.pt); + if (!(mask & (POLLIN | POLLERR | POLLHUP))) { + vm->vmhost->vcpuSemaTask[vcpuid] = current; + schedule_timeout(timeoutms * HZ / 1000); // convert to Hz + vm->vmhost->vcpuSemaTask[vcpuid] = NULL; + } +- current->state = TASK_RUNNING; ++ set_current_state(TASK_RUNNING); + poll_freewait(&table); + } + +@@ -2535,7 +2537,7 @@ HostIF_SemaphoreForceWakeup(VMDriver *vm, // IN: + FOR_EACH_VCPU_IN_SET(vcs, vcpuid) { + struct task_struct *t = vm->vmhost->vcpuSemaTask[vcpuid]; + vm->vmhost->vcpuSemaTask[vcpuid] = NULL; +- if (t && (t->state & TASK_INTERRUPTIBLE)) { ++ if (t && (compat_get_task_state(t) & TASK_INTERRUPTIBLE)) { + wake_up_process(t); + } + } ROF_EACH_VCPU_IN_SET(); |