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On 2006.08.08 17:39:37 +0300, Muli Ben-Yehuda wrote: > On Tue, Aug 08, 2006 at 07:32:51AM -0700, akpm@osdl.org wrote: > > > > The patch titled > > > > sys_getppid() oopses on debug kernel > > > > has been added to the -mm tree. Its filename is > > > > sys_getppid-oopses-on-debug-kernel.patch > > > > See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find > > out what to do about this > > > > ------------------------------------------------------ > > Subject: sys_getppid() oopses on debug kernel > > From: Kirill Korotaev <dev@sw.ru> > > > > sys_getppid() optimization can access a freed memory. On kernels with > > DEBUG_SLAB turned ON, this results in Oops. > > > > Signed-off-by: Kirill Korotaev <dev@openvz.org> > > Cc: <stable@kernel.org> > > Signed-off-by: Andrew Morton <akpm@osdl.org> > > I'm probably missing something, but is it really valid to access freed > kernel memory even if CONFIG_DEBUG_SLAB is off - as this patch does? There's a note right above the function that explains it: * NOTE! This depends on the fact that even if we _do_ * get an old value of "parent", we can happily dereference * the pointer (it was and remains a dereferencable kernel pointer * no matter what): we just can't necessarily trust the result * until we know that the parent pointer is valid. HTH Björn - 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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