Re: [run_timer_softirq] BUG: unable to handle kernel paging reques ...
Linus Torvalds writes: (Summary) In this case, the trapping instruction ends up decoding to In this case, the trapping instruction ends up decoding to 0: 4c 8d 6c c5 90 lea -0x70(%rbp,%rax,8),%r13 5:...
View ArticleRe: Kernel crash in free_pipe_info()
Linus Torvalds writes: (Summary) But as you say, we've had subtle races just due to the named pipes: But as you say, we've had subtle races just due to the named pipes: [...] subtle use-after-free of...
View ArticleRe: Kernel crash in free_pipe_info()
Linus Torvalds writes: (Summary) On Mon, Oct 30, 2017 at 3:14 PM, Linus Torvalds<torvalds@linux-foundation.org> So I tried to google for this oops, and the only oops I find is hat ppc one you...
View ArticleRe: Kernel crash in free_pipe_info()
Linus Torvalds writes: (Summary) That's the (bad) buf->ops pointer that was loaded from the somehow corrupted "buf". loaded from the somehow corrupted "buf". The values in all cases are The values...
View ArticleRe: Kernel crash in free_pipe_info()
Linus Torvalds writes: (Summary) We do free_pipe_info(inode->i_pipe); iput(inode); iput(inode); - we couldn't allocate any file at all: - we couldn't allocate any file at all:...
View ArticleRe: KASAN: use-after-free Read in __do_page_fault
Linus Torvalds writes: (Summary) An unfortunate issue with userfaultfd. unfortunate issue with userfaultfd. The suggested fix to simply look up pkey beforehand seems sane and simple. afterwards but...
View ArticleRe: [RFC/RFT PATCH 0/6] Switch GHES ioremap_page_range() to use fixmap
Linus Torvalds writes: (Summary) I *would* suggest just making the "add fixmap entries" commits with the code that actually uses them. There's no real reason to have two commits that just add two...
View ArticleRe: [RFC/RFT PATCH 0/6] Switch GHES ioremap_page_range() to use fixmap
Linus Torvalds writes: (Summary) wrote:[...] Lovely. Side note: it wasn't entirely obvious what restricted the ghes driver to only x86 and arm64. I had to look up the whole HAVE_ACPI_APEI dependency....
View ArticleRe: [RFC] Improving udelay/ndelay on platforms where that is possible
Linus Torvalds writes: (Summary) On Tue, Oct 31, 2017 at 9:15 AM, Marc Gonzalez<marc_gonzalez@sigmadesigns.com> We use the TSC, and ndelay() does the right thing too. the right thing too. I've...
View ArticleRe: [RFC] Improving udelay/ndelay on platforms where that is possible
Linus Torvalds writes: (Summary) On modern x86, as mentioned, the TSC is stable and fairly high frequency (it isn't really the gigahertz frequency that it reports - reading it takes time, and even...
View ArticleRe: [RFC] Improving udelay/ndelay on platforms where that is possible
Linus Torvalds writes: (Summary) But ... Side note: this is obviously a negative feedback circle, where because we know we can't do all that great in general, few platforms really bother to do as well...
View ArticleRe: Kernel crash in free_pipe_info()
Linus Torvalds writes: (Summary) And rather than being about "pipe->bufs[]" array, it's the pipe pointer itself that seems corrupted, and thus the oops happens in the account_pipe_buffers() code...
View ArticleRe: [PATCH 00/23] KAISER: unmap most of the kernel from userspace ...
Linus Torvalds writes: (Summary) Inconveniently, the people you cc'd on the actual patches did *not* get cc'd with this 00/23 cover letter email. get cc'd with this 00/23 cover letter email. Also, the...
View ArticleRe: KASAN: use-after-free Read in __do_page_fault
Linus Torvalds writes: (Summary) Then we wouldn't have a special case for userfaultfd at all. userfaultfd at all. I see the gdb issue, but I wonder if we shouldn't fix that differently by changing the...
View ArticleRe: [PATCH 00/23] KAISER: unmap most of the kernel from userspace ...
Linus Torvalds writes: (Summary) On Tue, Oct 31, 2017 at 4:44 PM, Dave Hansen<dave.hansen@linux.intel.com> wrote:[...] done via the code we add to native_set_pgd(). So the thing that made me...
View ArticleRe: [PATCH 00/23] KAISER: unmap most of the kernel from userspace ...
Linus Torvalds writes: (Summary) Most notably there are the cacheability things where we've had machine check exceptions when the same page is mapped non-cachable in user space and cacheable in kernel...
View ArticleRe: [PATCH 00/23] KAISER: unmap most of the kernel from userspace ...
Linus Torvalds writes: (Summary) On Wed, Nov 1, 2017 at 11:46 AM, Dave Hansen<dave.hansen@linux.intel.com> wrote:[...] The vmalloc()'d stacks definitely need the page table walk. Nasty. Ugh, yes....
View ArticleRe: [RFC] Improving udelay/ndelay on platforms where that is possible
Linus Torvalds writes: (Summary) That's very much *NOT* the case. That's very much *NOT* the case. Yes, there is a *fallback* for when somebody doesn't do ndelay() at all, but that doesn't make it the...
View ArticleRe: [RFC] Improving udelay/ndelay on platforms where that is possible
Linus Torvalds writes: (Summary) If you are doing a driver that needs that kind of delay granularity, you had better already know exactly how long it takes to read the status register, and just do that...
View ArticleRe: [PATCH 02/23] x86, kaiser: do not set _PAGE_USER for init_mm p ...
Linus Torvalds writes: (Summary) I actually think there may be two issues here: I actually think there may be two issues here: - vsyscall isn't even used much - if any - any more - vsyscall isn't even...
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