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| author | Michael Ellerman <mpe@ellerman.id.au> | 2021-02-02 16:02:06 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-02-08 17:10:16 +0300 |
| commit | 0ecf6a9e47d825b7dddfebca738386b809e59a94 (patch) | |
| tree | e3074c3b0caa3e00e4f053caf4879296702319ca /arch/powerpc/kernel | |
| parent | 73287caa9210ded6066833195f4335f7f688a46b (diff) | |
| download | linux-0ecf6a9e47d825b7dddfebca738386b809e59a94.tar.xz | |
powerpc/64: Make stack tracing work during very early boot
If we try to stack trace very early during boot, either due to a
WARN/BUG or manual dump_stack(), we will oops in
valid_emergency_stack() when we try to dereference the paca_ptrs
array.
The fix is simple, we just return false if paca_ptrs isn't allocated
yet. The stack pointer definitely isn't part of any emergency stack
because we haven't allocated any yet.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210202130207.1303975-1-mpe@ellerman.id.au
Diffstat (limited to 'arch/powerpc/kernel')
| -rw-r--r-- | arch/powerpc/kernel/process.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 8520ed5ae144..e296440e9d16 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -2047,6 +2047,9 @@ static inline int valid_emergency_stack(unsigned long sp, struct task_struct *p, unsigned long stack_page; unsigned long cpu = task_cpu(p); + if (!paca_ptrs) + return 0; + stack_page = (unsigned long)paca_ptrs[cpu]->emergency_sp - THREAD_SIZE; if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes) return 1; |