Messages in this thread Patch in this message | | | Date | Fri, 13 Apr 2007 17:19:14 +0100 (BST) | From | Hugh Dickins <> | Subject | [PATCH mm] fix i386 get_gate_vma oops |
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Fix oops from i386-make-compat_vdso-runtime-selectable.patch.
Even mingetty at system startup finds it easy to trigger an oops while reading /proc/PID/maps: though it has a good hold on the mm itself, that cannot stop exit_mm() from resetting tsk->mm to NULL.
(It is usually show_map()'s call to get_gate_vma() which oopses, and I expect we could change that to check priv->tail_vma instead; but no matter, even m_start()'s call just after get_task_mm() is racy.)
Signed-off-by: Hugh Dickins <hugh@veritas.com>
--- 2.6.21-rc6-mm1/arch/i386/kernel/sysenter.c 2007-04-10 11:37:23.000000000 +0100 +++ linux/arch/i386/kernel/sysenter.c 2007-04-13 16:43:45.000000000 +0100 @@ -326,8 +326,10 @@ const char *arch_vma_name(struct vm_area struct vm_area_struct *get_gate_vma(struct task_struct *tsk) { + struct mm_struct *mm = tsk->mm; + /* Check to see if this task was created in compat vdso mode */ - if (tsk->mm->context.vdso == (void *)VDSO_HIGH_BASE) + if (mm && mm->context.vdso == (void *)VDSO_HIGH_BASE) return &gate_vma; return NULL; } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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