- 17 Apr, 2019 29 commits
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Thomas Gleixner authored
Preparatory change for disentangling the irq stack union as a prerequisite for irq stacks with guard pages. Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: "Chang S. Bae" <chang.seok.bae@intel.com> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Nicolai Stange <nstange@suse.de> Cc: Pavel Tatashin <pasha.tatashin@oracle.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Cc: x86-ml <x86@kernel.org> Cc: Yi Wang <wang.yi59@zte.com.cn> Link: https://lkml.kernel.org/r/20190414160146.177558566@linutronix.de
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Thomas Gleixner authored
irq_ctx_init() crashes hard on page allocation failures. While that's ok during early boot, it's just wrong in the CPU hotplug bringup code. Check the page allocation failure and return -ENOMEM and handle it at the call sites. On early boot the only way out is to BUG(), but on CPU hotplug there is no reason to crash, so just abort the operation. Rename the function to something more sensible while at it. Signed-off-by:
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Thomas Gleixner authored
irq_ctx_init() is invoked from native_init_IRQ() or from xen_init_IRQ() code. There is no reason to have this split. The interrupt stacks must be allocated no matter what. Invoke it from init_IRQ() before invoking the native or XEN init implementation. Signed-off-by:
Juergen Gross <jgross@suse.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Josh Abraham <j.abraham1776@gmail.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Nicolai Stange <nstange@suse.de> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: x86-ml <x86@kernel.org> Cc: xen-devel@lists.xenproject.org Link: https://lkml.kernel.org/r/20190414160146.001162606@linutronix.de
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Thomas Gleixner authored
Preparatory patch to share code with 32bit. No functional changes. Signed-off-by:
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Thomas Gleixner authored
The percpu storage holds a pointer to the stack not the stack itself. Rename it before sharing struct irq_stack with 64-bit. No functional changes. Signed-off-by:
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Thomas Gleixner authored
There is no reason to have an u32 array in struct irq_stack. The only purpose of the array is to size the struct properly. Preparatory change for sharing struct irq_stack with 64-bit. Signed-off-by:
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Thomas Gleixner authored
On 32-bit IRQ_STACK_SIZE is the same as THREAD_SIZE. To allow sharing struct irq_stack with 32-bit, define IRQ_STACK_SIZE for 32-bit and use it for struct irq_stack. No functional change. Signed-off-by:
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Thomas Gleixner authored
The current implementation of in_exception_stack() iterates over the exception stacks array. Most of the time this is an useless exercise, but even for the actual use cases (perf and ftrace) it takes at least 2 iterations to get to the NMI stack. As the exception stacks and the guard pages are page aligned the loop can be avoided completely. Add a initial check whether the stack pointer is inside the full exception stack area and leave early if not. Create a lookup table which describes the stack area. The table index is the page offset from the beginning of the exception stacks. So for any given stack pointer the page offset is computed and a lookup in the description table is performed. If it is inside a guard page, return. If not, use the descriptor to fill in the info structure. The table is filled at compile time and for the !KASAN case the interesting page descriptors exactly fit into a single cache line. Just the last guard page descriptor is in the next cacheline, but that should not be accessed in the regular case. Signed-off-by:
Josh Poimboeuf <jpoimboe@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20190414160145.543320386@linutronix.de
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Thomas Gleixner authored
The debug IST stack is actually two separate debug stacks to handle #DB recursion. This is required because the CPU starts always at top of stack on exception entry, which means on #DB recursion the second #DB would overwrite the stack of the first. The low level entry code therefore adjusts the top of stack on entry so a secondary #DB starts from a different stack page. But the stack pages are adjacent without a guard page between them. Split the debug stack into 3 stacks which are separated by guard pages. The 3rd stack is never mapped into the cpu_entry_area and is only there to catch triple #DB nesting: --- top of DB_stack <- Initial stack --- end of DB_stack guard page --- top of DB1_stack <- Top of stack after entering first #DB --- end of DB1_stack guard page --- top of DB2_stack <- Top of stack after entering second #DB --- end of DB2_stack guard page If DB2 would not act as the final guard hole, a second #DB would point the top of #DB stack to the stack below #DB1 which would be valid and not catch the not so desired triple nesting. The backing store does not allocate any memory for DB2 and its guard page as it is not going to be mapped into the cpu_entry_area. - Adjust the low level entry code so it adjusts top of #DB with the offset between the stacks instead of exception stack size. - Make the dumpstack code aware of the new stacks. - Adjust the in_debug_stack() implementation and move it into the NMI code where it belongs. As this is NMI hotpath code, it just checks the full area between top of DB_stack and bottom of DB1_stack without checking for the guard page. That's correct because the NMI cannot hit a stackpointer pointing to the guard page between DB and DB1 stack. Even if it would, then the NMI operation still is unaffected, but the resume of the debug exception on the topmost DB stack will crash by touching the guard page. [ bp: Make exception_stack_names static const char * const ] Suggested-by:Andy Lutomirski <luto@kernel.org> Signed-off-by:
Sean Christopherson <sean.j.christopherson@intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: "Chang S. Bae" <chang.seok.bae@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joerg Roedel <jroedel@suse.de> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: linux-doc@vger.kernel.org Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qian Cai <cai@lca.pw> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20190414160145.439944544@linutronix.de
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Thomas Gleixner authored
All usage sites which expected that the exception stacks in the CPU entry area are mapped linearly are fixed up. Enable guard pages between the IST stacks. Signed-off-by:
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Thomas Gleixner authored
The entry order of the TSS.IST array and the order of the stack storage/mapping are not required to be the same. With the upcoming split of the debug stack this is going to fall apart as the number of TSS.IST array entries stays the same while the actual stacks are increasing. Make them separate so that code like dumpstack can just utilize the mapping order. The IST index is solely required for the actual TSS.IST array initialization. Signed-off-by:
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Thomas Gleixner authored
All users gone. Signed-off-by:
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Thomas Gleixner authored
Convert the TSS.IST setup code to use the cpu entry area information directly instead of assuming a linear mapping of the IST stacks. The store to orig_ist[] is no longer required as there are no users anymore. This is the last preparatory step towards IST guard pages. Signed-off-by:
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Thomas Gleixner authored
The orig_ist[] array is a shadow copy of the IST array in the TSS. The reason why it exists is that older kernels used two TSS variants with different pointers into the debug stack. orig_ist[] contains the real starting points. There is no point anymore to do so because the same information can be retrieved using the base address of the cpu entry area mapping and the offsets of the various exception stacks. No functional change. Preparation for removing orig_ist. Cc: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by:
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Thomas Gleixner authored
The orig_ist[] array is a shadow copy of the IST array in the TSS. The reason why it exists is that older kernels used two TSS variants with different pointers into the debug stack. orig_ist[] contains the real starting points. There is no point anymore to do so because the same information can be retrieved using the base address of the cpu entry area mapping and the offsets of the various exception stacks. No functional change. Preparation for removing orig_ist. Signed-off-by:
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Thomas Gleixner authored
The orig_ist[] array is a shadow copy of the IST array in the TSS. The reason why it exists is that older kernels used two TSS variants with different pointers into the debug stack. orig_ist[] contains the real starting points. There is no point anymore to do so because the same information can be retrieved using the base address of the cpu entry area mapping and the offsets of the various exception stacks. No functional change. Preparation for removing orig_ist. Signed-off-by:
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Thomas Gleixner authored
Store a pointer to the per cpu entry area exception stack mappings to allow fast retrieval. Required for converting various places from using the shadow IST array to directly doing address calculations on the actual mapping address. Signed-off-by:
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Thomas Gleixner authored
To allow guard pages between the IST stacks each stack needs to be mapped individually. Signed-off-by:
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Thomas Gleixner authored
At the moment everything assumes a full linear mapping of the various exception stacks. Adding guard pages to the cpu entry area mapping of the exception stacks will break that assumption. As a preparatory step convert both the real storage and the effective mapping in the cpu entry area from character arrays to structures. To ensure that both arrays have the same ordering and the same size of the individual stacks fill the members with a macro. The guard size is the only difference between the two resulting structures. For now both have guard size 0 until the preparation of all usage sites is done. Provide a couple of helper macros which are used in the following conversions. Signed-off-by:
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Thomas Gleixner authored
No point in retrieving the entry area pointer over and over. Do it once and use unsigned int for 'cpu' everywhere. Signed-off-by:
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Thomas Gleixner authored
The defines for the exception stack (IST) array in the TSS are using the SDM convention IST1 - IST7. That causes all sorts of code to subtract 1 for array indices related to IST. That's confusing at best and does not provide any value. Make the indices zero based and fixup the usage sites. The only code which needs to adjust the 0 based index is the interrupt descriptor setup which needs to add 1 now. Signed-off-by:
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Thomas Gleixner authored
Nothing requires those for 32bit builds. Signed-off-by:
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Thomas Gleixner authored
Nothing uses that and before people get the wrong ideas, get rid of it. Signed-off-by:
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Thomas Gleixner authored
Commit d8ba61ba ("x86/entry/64: Don't use IST entry for #BP stack") removed the last user but left the macro around. Signed-off-by:
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Thomas Gleixner authored
On x86, stacks go top to bottom, but the stack overflow check uses it the other way round, which is just confusing. Clean it up and sanitize the warning string a bit. Signed-off-by:
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Andy Lutomirski authored
stack_overflow_check() is using both irq_stack_ptr and irq_stack_union to find the IRQ stack. That's going to break when vmapped irq stacks are introduced. Change it to just use irq_stack_ptr. Signed-off-by:
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Andy Lutomirski authored
The get_stack_info() function is off-by-one when checking whether an address is on a IRQ stack or a IST stack. This prevents an overflowed IRQ or IST stack from being dumped properly. [ tglx: Do the same for 32-bit ] Signed-off-by:
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Thomas Gleixner authored
Commit 37fe6a42 ("x86: Check stack overflow in detail") added a broad check for the full exception stack area, i.e. it considers the full exception stack area as valid. That's wrong in two aspects: 1) It does not check the individual areas one by one 2) #DF, NMI and #MCE are not enabling interrupts which means that a regular device interrupt cannot happen in their context. In fact if a device interrupt hits one of those IST stacks that's a bug because some code path enabled interrupts while handling the exception. Limit the check to the #DB stack and consider all other IST stacks as 'overflow' or invalid. Signed-off-by:
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Qian Cai authored
store_stackinfo() does not seem used in actual SLAB debugging. Potentially, it could be added to check_poison_obj() to provide more information but this seems like an overkill due to the declining popularity of SLAB, so just remove it instead. Signed-off-by:
Qian Cai <cai@lca.pw> Signed-off-by:
Vlastimil Babka <vbabka@suse.cz> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: linux-mm <linux-mm@kvack.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: rientjes@google.com Cc: sean.j.christopherson@intel.com Link: https://lkml.kernel.org/r/20190416142258.18694-1-cai@lca.pw
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- 14 Apr, 2019 6 commits
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Linus Torvalds authored
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Linus Torvalds authored
Merge page ref overflow branch. Jann Horn reported that he can overflow the page ref count with sufficient memory (and a filesystem that is intentionally extremely slow). Admittedly it's not exactly easy. To have more than four billion references to a page requires a minimum of 32GB of kernel memory just for the pointers to the pages, much less any metadata to keep track of those pointers. Jann needed a total of 140GB of memory and a specially crafted filesystem that leaves all reads pending (in order to not ever free the page references and just keep adding more). Still, we have a fairly straightforward way to limit the two obvious user-controllable sources of page references: direct-IO like page references gotten through get_user_pages(), and the splice pipe page duplication. So let's just do that. * branch page-refs: fs: prevent page refcount overflow in pipe_buf_get mm: prevent get_user_pages() from overflowing page refcount mm: add 'try_get_page()' helper function mm: make page ref count overflow check tighter and more explicit
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Matthew Wilcox authored
Change pipe_buf_get() to return a bool indicating whether it succeeded in raising the refcount of the page (if the thing in the pipe is a page). This removes another mechanism for overflowing the page refcount. All callers converted to handle a failure. Reported-by:
Jann Horn <jannh@google.com> Signed-off-by:
Matthew Wilcox <willy@infradead.org> Cc: stable@kernel.org Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Linus Torvalds authored
If the page refcount wraps around past zero, it will be freed while there are still four billion references to it. One of the possible avenues for an attacker to try to make this happen is by doing direct IO on a page multiple times. This patch makes get_user_pages() refuse to take a new page reference if there are already more than two billion references to the page. Reported-by:
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Linus Torvalds authored
This is the same as the traditional 'get_page()' function, but instead of unconditionally incrementing the reference count of the page, it only does so if the count was "safe". It returns whether the reference count was incremented (and is marked __must_check, since the caller obviously has to be aware of it). Also like 'get_page()', you can't use this function unless you already had a reference to the page. The intent is that you can use this exactly like get_page(), but in situations where you want to limit the maximum reference count. The code currently does an unconditional WARN_ON_ONCE() if we ever hit the reference count issues (either zero or negative), as a notification that the conditional non-increment actually happened. NOTE! The count access for the "safety" check is inherently racy, but that doesn't matter since the buffer we use is basically half the range of the reference count (ie we look at the sign of the count). Acked-by:
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Linus Torvalds authored
We have a VM_BUG_ON() to check that the page reference count doesn't underflow (or get close to overflow) by checking the sign of the count. That's all fine, but we actually want to allow people to use a "get page ref unless it's already very high" helper function, and we want that one to use the sign of the page ref (without triggering this VM_BUG_ON). Change the VM_BUG_ON to only check for small underflows (or _very_ close to overflowing), and ignore overflows which have strayed into negative territory. Acked-by:
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- 13 Apr, 2019 5 commits
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git://git.kernel.dk/linux-blockLinus Torvalds authored
Pull block fixes from Jens Axboe: "Set of fixes that should go into this round. This pull is larger than I'd like at this time, but there's really no specific reason for that. Some are fixes for issues that went into this merge window, others are not. Anyway, this contains: - Hardware queue limiting for virtio-blk/scsi (Dongli) - Multi-page bvec fixes for lightnvm pblk - Multi-bio dio error fix (Jason) - Remove the cache hint from the io_uring tool side, since we didn't move forward with that (me) - Make io_uring SETUP_SQPOLL root restricted (me) - Fix leak of page in error handling for pc requests (Jérôme) - Fix BFQ regression introduced in this merge window (Paolo) - Fix break logic for bio segment iteration (Ming) - Fix NVMe cancel request error handling (Ming) - NVMe pull request with two fixes (Christoph): - fix the initial CSN for nvme-fc (James) - handle log page offsets properly in the target (Keith)" * tag 'for-linus-20190412' of git://git.kernel.dk/linux-block: block: fix the return errno for direct IO nvmet: fix discover log page when offsets are used nvme-fc: correct csn initialization and increments on error block: do not leak memory in bio_copy_user_iov() lightnvm: pblk: fix crash in pblk_end_partial_read due to multipage bvecs nvme: cancel request synchronously blk-mq: introduce blk_mq_complete_request_sync() scsi: virtio_scsi: limit number of hw queues by nr_cpu_ids virtio-blk: limit number of hw queues by nr_cpu_ids block, bfq: fix use after free in bfq_bfqq_expire io_uring: restrict IORING_SETUP_SQPOLL to root tools/io_uring: remove IOCQE_FLAG_CACHEHIT block: don't use for-inside-for in bio_for_each_segment_all -
git://git.linux-nfs.org/projects/trondmy/linux-nfsLinus Torvalds authored
Pull NFS client bugfixes from Trond Myklebust: "Highlights include: Stable fix: - Fix a deadlock in close() due to incorrect draining of RDMA queues Bugfixes: - Revert "SUNRPC: Micro-optimise when the task is known not to be sleeping" as it is causing stack overflows - Fix a regression where NFSv4 getacl and fs_locations stopped working - Forbid setting AF_INET6 to "struct sockaddr_in"->sin_family. - Fix xfstests failures due to incorrect copy_file_range() return values" * tag 'nfs-for-5.1-4' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: Revert "SUNRPC: Micro-optimise when the task is known not to be sleeping" NFSv4.1 fix incorrect return value in copy_file_range xprtrdma: Fix helper that drains the transport NFS: Fix handling of reply page vector NFS: Forbid setting AF_INET6 to "struct sockaddr_in"->sin_family. -
git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsiLinus Torvalds authored
Pull SCSI fix from James Bottomley: "One obvious fix for a ciostor data corruption on error bug" * tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: scsi: csiostor: fix missing data copy in csio_scsi_err_handler()
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git://git.kernel.org/pub/scm/linux/kernel/git/clk/linuxLinus Torvalds authored
Pull clk fixes from Stephen Boyd: "Here's more than a handful of clk driver fixes for changes that came in during the merge window: - Fix the AT91 sama5d2 programmable clk prescaler formula - A bunch of Amlogic meson clk driver fixes for the VPU clks - A DMI quirk for Intel's Bay Trail SoC's driver to properly mark pmc clks as critical only when really needed - Stop overwriting CLK_SET_RATE_PARENT flag in mediatek's clk gate implementation - Use the right structure to test for a frequency table in i.MX's PLL_1416x driver" * tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux: clk: imx: Fix PLL_1416X not rounding rates clk: mediatek: fix clk-gate flag setting platform/x86: pmc_atom: Drop __initconst on dmi table clk: x86: Add system specific quirk to mark clocks as critical clk: meson: vid-pll-div: remove warning and return 0 on invalid config clk: meson: pll: fix rounding and setting a rate that matches precisely clk: meson-g12a: fix VPU clock parents clk: meson: g12a: fix VPU clock muxes mask clk: meson-gxbb: round the vdec dividers to closest clk: at91: fix programmable clock for sama5d2 -
git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pciLinus Torvalds authored
Pull PCI fixes from Bjorn Helgaas: - Add a DMA alias quirk for another Marvell SATA device (Andre Przywara) - Fix a pciehp regression that broke safe removal of devices (Sergey Miroshnichenko) * tag 'pci-v5.1-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: PCI: pciehp: Ignore Link State Changes after powering off a slot PCI: Add function 1 DMA alias quirk for Marvell 9170 SATA controller
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