642ffab5fc
Trying to grab locks during cngrab() when entering the debugger is deadlock prone as all other CPUs are already halted (and thus unable to release locks) when cngrab() is invoked. One could instead use try-locks. However, the case that the try-lock fails still has to be handled. In addition, if the try-lock works it doesn't provide any greater ordering guarantees than is already provided by entering and exiting DDB. It is simpler to define a simpler path for the case that the try-lock would fail and always use that when entering DDB. Messing with timers, etc. when entering DDB is dubious even if the try-lock succeeds. This patch attempts to use the smallest possible set of operations to grab the vt(4) console when entering DDB without using any locks. Reviewed by: emaste Tested by: Matthew Macy MFC after: 1 week |
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| .. | ||
| colors | ||
| font | ||
| hw | ||
| logo | ||
| vt_buf.c | ||
| vt_consolectl.c | ||
| vt_core.c | ||
| vt_cpulogos.c | ||
| vt_font.c | ||
| vt_sysmouse.c | ||
| vt.h | ||