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Disable interrupts while in kdb_trap() to handle cases where the caller

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doesn't do it.  This fixes all known causes of "Context switches not
allowed in the debugger" in mi_switch().  The main cause was trap_fatal()
calling kdb_trap() with interrupts enabled.  Switching to ithreads for
interrupt handling then made fatal traps more fatal and harder to debug.
The problem was limited in -current because most interrupt handlers are
blocked by Giant, but it occurred almost deterministically for me because
my clock interrupt handlers are non-fast and not blocked by Giant.
This commit is contained in:
Bruce Evans 2003-03-24 10:17:14 +00:00
parent 5efb531d6c
commit f261b1f35f
2 changed files with 14 additions and 0 deletions
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7
sys/amd64/amd64/db_interface.c
View File

@ -77,6 +77,7 @@ rss(void)
int
kdb_trap(int type, int code, struct i386_saved_state *regs)
{
u_int ef;
volatile int ddb_mode = !(boothowto & RB_GDB);
/*
@ -96,6 +97,9 @@ kdb_trap(int type, int code, struct i386_saved_state *regs)
return (0);
}
ef = read_eflags();
disable_intr();
switch (type) {
case T_BPTFLT: /* breakpoint */
case T_TRCTRAP: /* debug exception */
@ -216,6 +220,9 @@ kdb_trap(int type, int code, struct i386_saved_state *regs)
regs->tf_fs = ddb_regs.tf_fs & 0xffff;
regs->tf_cs = ddb_regs.tf_cs & 0xffff;
regs->tf_ds = ddb_regs.tf_ds & 0xffff;
write_eflags(ef);
return (1);
}

7
sys/i386/i386/db_interface.c
View File

@ -77,6 +77,7 @@ rss(void)
int
kdb_trap(int type, int code, struct i386_saved_state *regs)
{
u_int ef;
volatile int ddb_mode = !(boothowto & RB_GDB);
/*
@ -96,6 +97,9 @@ kdb_trap(int type, int code, struct i386_saved_state *regs)
return (0);
}
ef = read_eflags();
disable_intr();
switch (type) {
case T_BPTFLT: /* breakpoint */
case T_TRCTRAP: /* debug exception */
@ -216,6 +220,9 @@ kdb_trap(int type, int code, struct i386_saved_state *regs)
regs->tf_fs = ddb_regs.tf_fs & 0xffff;
regs->tf_cs = ddb_regs.tf_cs & 0xffff;
regs->tf_ds = ddb_regs.tf_ds & 0xffff;
write_eflags(ef);
return (1);
}