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| author | Paul Gortmaker <paul.gortmaker@windriver.com> | 2014-04-29 15:25:17 -0400 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2014-05-20 10:54:06 +1000 |
| commit | 21f585073d6347651f2262da187606fa1c4ee16d (patch) | |
| tree | 5ec5947a36e0a7e7fe458d13523d4036cc748ff1 /arch/powerpc/kernel/process.c | |
| parent | 04c32a516806ec74b62048baf4cddcbb840927db (diff) | |
| download | linux-21f585073d6347651f2262da187606fa1c4ee16d.tar.gz linux-21f585073d6347651f2262da187606fa1c4ee16d.tar.bz2 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/process.c')
| -rw-r--r-- | arch/powerpc/kernel/process.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index f895a5062287..8a1edbe26b8f 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -496,7 +496,7 @@ static inline int set_dawr(struct arch_hw_breakpoint *brk) return 0; } -void set_breakpoint(struct arch_hw_breakpoint *brk) +void __set_breakpoint(struct arch_hw_breakpoint *brk) { __get_cpu_var(current_brk) = *brk; @@ -506,6 +506,13 @@ void set_breakpoint(struct arch_hw_breakpoint *brk) set_dabr(brk); } +void set_breakpoint(struct arch_hw_breakpoint *brk) +{ + preempt_disable(); + __set_breakpoint(brk); + preempt_enable(); +} + #ifdef CONFIG_PPC64 DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array); #endif @@ -835,7 +842,7 @@ struct task_struct *__switch_to(struct task_struct *prev, */ #ifndef CONFIG_HAVE_HW_BREAKPOINT if (unlikely(!hw_brk_match(&__get_cpu_var(current_brk), &new->thread.hw_brk))) - set_breakpoint(&new->thread.hw_brk); + __set_breakpoint(&new->thread.hw_brk); #endif /* CONFIG_HAVE_HW_BREAKPOINT */ #endif |