d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Fix a deadlock condition with tlb shootdown ipi delivery. Since ipis are

Browse Source 
not blocked by raising the pil, a reciever may be interrupted while holding
a spinlock.  If the sender does not defer interrupts throughout the entire
operation it may be interrupted and try to acquire a spinlock held by a
reciever, leading to a deadlock due to the synchronization used by the
ipi handlers themselves.

Submitted by:	tmm
This commit is contained in:
jake 2002-03-23 04:20:00 +00:00
parent d0a6197c00
commit f11b0f8cfb
1 changed files with 17 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
sys/sparc64/include/tlb.h
View File

@ -101,6 +101,18 @@ tlb_context_demap(struct pmap *pm)
void *cookie;
u_long s;
/*
* It is important that we are not interrupted or preempted while
* doing the IPIs. The interrupted CPU may hold locks, and since
* it will wait for the CPU that sent the IPI, this can lead
* to a deadlock when an interrupt comes in on that CPU and it's
* handler tries to grab one of that locks. This will only happen for
* spin locks, but these IPI types are delivered even if normal
* interrupts are disabled, so the lock critical section will not
* protect the target processor from entering the IPI handler with
* the lock held.
*/
critical_enter();
cookie = ipi_tlb_context_demap(pm);
if (pm->pm_active & PCPU_GET(cpumask)) {
KASSERT(pm->pm_context[PCPU_GET(cpuid)] != -1,
@ -112,6 +124,7 @@ tlb_context_demap(struct pmap *pm)
intr_restore(s);
}
ipi_wait(cookie);
critical_exit();
}
static __inline void
@ -121,6 +134,7 @@ tlb_page_demap(u_int tlb, struct pmap *pm, vm_offset_t va)
void *cookie;
u_long s;
critical_enter();
cookie = ipi_tlb_page_demap(tlb, pm, va);
if (pm->pm_active & PCPU_GET(cpumask)) {
KASSERT(pm->pm_context[PCPU_GET(cpuid)] != -1,
@ -142,6 +156,7 @@ tlb_page_demap(u_int tlb, struct pmap *pm, vm_offset_t va)
intr_restore(s);
}
ipi_wait(cookie);
critical_exit();
}
static __inline void
@ -152,6 +167,7 @@ tlb_range_demap(struct pmap *pm, vm_offset_t start, vm_offset_t end)
u_long flags;
u_long s;
critical_enter();
cookie = ipi_tlb_range_demap(pm, start, end);
if (pm->pm_active & PCPU_GET(cpumask)) {
KASSERT(pm->pm_context[PCPU_GET(cpuid)] != -1,
@ -170,6 +186,7 @@ tlb_range_demap(struct pmap *pm, vm_offset_t start, vm_offset_t end)
intr_restore(s);
}
ipi_wait(cookie);
critical_exit();
}
#define tlb_tte_demap(tte, pm) \