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authorPaul Gortmaker <paul.gortmaker@windriver.com>2014-04-29 21:25:17 +0200
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2014-05-20 02:54:06 +0200
commit21f585073d6347651f2262da187606fa1c4ee16d (patch)
tree5ec5947a36e0a7e7fe458d13523d4036cc748ff1 /arch/powerpc/kernel/hw_breakpoint.c
parentpowerpc: Drop return value from set_breakpoint as it is unused (diff)
downloadlinux-21f585073d6347651f2262da187606fa1c4ee16d.tar.xz
linux-21f585073d6347651f2262da187606fa1c4ee16d.zip
powerpc: Fix smp_processor_id() in preemptible splat in set_breakpoint
Currently, on 8641D, which doesn't set CONFIG_HAVE_HW_BREAKPOINT we get the following splat: BUG: using smp_processor_id() in preemptible [00000000] code: login/1382 caller is set_breakpoint+0x1c/0xa0 CPU: 0 PID: 1382 Comm: login Not tainted 3.15.0-rc3-00041-g2aafe1a4d451 #1 Call Trace: [decd5d80] [c0008dc4] show_stack+0x50/0x158 (unreliable) [decd5dc0] [c03c6fa0] dump_stack+0x7c/0xdc [decd5de0] [c01f8818] check_preemption_disabled+0xf4/0x104 [decd5e00] [c00086b8] set_breakpoint+0x1c/0xa0 [decd5e10] [c00d4530] flush_old_exec+0x2bc/0x588 [decd5e40] [c011c468] load_elf_binary+0x2ac/0x1164 [decd5ec0] [c00d35f8] search_binary_handler+0xc4/0x1f8 [decd5ef0] [c00d4ee8] do_execve+0x3d8/0x4b8 [decd5f40] [c001185c] ret_from_syscall+0x0/0x38 --- Exception: c01 at 0xfeee554 LR = 0xfeee7d4 The call path in this case is: flush_thread --> set_debug_reg_defaults --> set_breakpoint --> __get_cpu_var Since preemption is enabled in the cleanup of flush thread, and there is no need to disable it, introduce the distinction between set_breakpoint and __set_breakpoint, leaving only the flush_thread instance as the current user of set_breakpoint. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/hw_breakpoint.c')
-rw-r--r--arch/powerpc/kernel/hw_breakpoint.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index b0a1792279bb..0bb5918faaaf 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -72,7 +72,7 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
* If so, DABR will be populated in single_step_dabr_instruction().
*/
if (current->thread.last_hit_ubp != bp)
- set_breakpoint(info);
+ __set_breakpoint(info);
return 0;
}
@@ -198,7 +198,7 @@ void thread_change_pc(struct task_struct *tsk, struct pt_regs *regs)
info = counter_arch_bp(tsk->thread.last_hit_ubp);
regs->msr &= ~MSR_SE;
- set_breakpoint(info);
+ __set_breakpoint(info);
tsk->thread.last_hit_ubp = NULL;
}
@@ -284,7 +284,7 @@ int __kprobes hw_breakpoint_handler(struct die_args *args)
if (!(info->type & HW_BRK_TYPE_EXTRANEOUS_IRQ))
perf_bp_event(bp, regs);
- set_breakpoint(info);
+ __set_breakpoint(info);
out:
rcu_read_unlock();
return rc;
@@ -316,7 +316,7 @@ int __kprobes single_step_dabr_instruction(struct die_args *args)
if (!(info->type & HW_BRK_TYPE_EXTRANEOUS_IRQ))
perf_bp_event(bp, regs);
- set_breakpoint(info);
+ __set_breakpoint(info);
current->thread.last_hit_ubp = NULL;
/*