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2022-05-08stackleak: rework stack high bound handlingMark Rutland
Prior to returning to userspace, we reset current->lowest_stack to a reasonable high bound. Currently we do this by subtracting the arbitrary value `THREAD_SIZE/64` from the top of the stack, for reasons lost to history. Looking at configurations today: * On i386 where THREAD_SIZE is 8K, the bound will be 128 bytes. The pt_regs at the top of the stack is 68 bytes (with 0 to 16 bytes of padding above), and so this covers an additional portion of 44 to 60 bytes. * On x86_64 where THREAD_SIZE is at least 16K (up to 32K with KASAN) the bound will be at least 256 bytes (up to 512 with KASAN). The pt_regs at the top of the stack is 168 bytes, and so this cover an additional 88 bytes of stack (up to 344 with KASAN). * On arm64 where THREAD_SIZE is at least 16K (up to 64K with 64K pages and VMAP_STACK), the bound will be at least 256 bytes (up to 1024 with KASAN). The pt_regs at the top of the stack is 336 bytes, so this can fall within the pt_regs, or can cover an additional 688 bytes of stack. Clearly the `THREAD_SIZE/64` value doesn't make much sense -- in the worst case, this will cause more than 600 bytes of stack to be erased for every syscall, even if actual stack usage were substantially smaller. This patches makes this slightly less nonsensical by consistently resetting current->lowest_stack to the base of the task pt_regs. For clarity and for consistency with the handling of the low bound, the generation of the high bound is split into a helper with commentary explaining why. Since the pt_regs at the top of the stack will be clobbered upon the next exception entry, we don't need to poison these at exception exit. By using task_pt_regs() as the high stack boundary instead of current_top_of_stack() we avoid some redundant poisoning, and the compiler can share the address generation between the poisoning and resetting of `current->lowest_stack`, making the generated code more optimal. It's not clear to me whether the existing `THREAD_SIZE/64` offset was a dodgy heuristic to skip the pt_regs, or whether it was attempting to minimize the number of times stackleak_check_stack() would have to update `current->lowest_stack` when stack usage was shallow at the cost of unconditionally poisoning a small portion of the stack for every exit to userspace. For now I've simply removed the offset, and if we need/want to minimize updates for shallow stack usage it should be easy to add a better heuristic atop, with appropriate commentary so we know what's going on. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Popov <alex.popov@linux.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220427173128.2603085-7-mark.rutland@arm.com
2022-05-08stackleak: clarify variable namesMark Rutland
The logic within __stackleak_erase() can be a little hard to follow, as `boundary` switches from being the low bound to the high bound mid way through the function, and `kstack_ptr` is used to represent the start of the region to erase while `boundary` represents the end of the region to erase. Make this a little clearer by consistently using clearer variable names. The `boundary` variable is removed, the bounds of the region to erase are described by `erase_low` and `erase_high`, and bounds of the task stack are described by `task_stack_low` and `task_stack_high`. As the same time, remove the comment above the variables, since it is unclear whether it's intended as rationale, a complaint, or a TODO, and is more confusing than helpful. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Popov <alex.popov@linux.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220427173128.2603085-6-mark.rutland@arm.com
2022-05-08stackleak: rework stack low bound handlingMark Rutland
In stackleak_task_init(), stackleak_track_stack(), and __stackleak_erase(), we open-code skipping the STACK_END_MAGIC at the bottom of the stack. Each case is implemented slightly differently, and only the __stackleak_erase() case is commented. In stackleak_task_init() and stackleak_track_stack() we unconditionally add sizeof(unsigned long) to the lowest stack address. In stackleak_task_init() we use end_of_stack() for this, and in stackleak_track_stack() we use task_stack_page(). In __stackleak_erase() we handle this by detecting if `kstack_ptr` has hit the stack end boundary, and if so, conditionally moving it above the magic. This patch adds a new stackleak_task_low_bound() helper which is used in all three cases, which unconditionally adds sizeof(unsigned long) to the lowest address on the task stack, with commentary as to why. This uses end_of_stack() as stackleak_task_init() did prior to this patch, as this is consistent with the code in kernel/fork.c which initializes the STACK_END_MAGIC value. In __stackleak_erase() we no longer need to check whether we've spilled into the STACK_END_MAGIC value, as stackleak_track_stack() ensures that `current->lowest_stack` stops immediately above this, and similarly the poison scan will stop immediately above this. For stackleak_task_init() and stackleak_track_stack() this results in no change to code generation. For __stackleak_erase() the generated assembly is slightly simpler and shorter. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Popov <alex.popov@linux.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220427173128.2603085-5-mark.rutland@arm.com
2022-05-08stackleak: remove redundant checkMark Rutland
In __stackleak_erase() we check that the `erase_low` value derived from `current->lowest_stack` is above the lowest legitimate stack pointer value, but this is already enforced by stackleak_track_stack() when recording the lowest stack value. Remove the redundant check. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Popov <alex.popov@linux.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220427173128.2603085-4-mark.rutland@arm.com
2022-05-08stackleak: move skip_erasing() check earlierMark Rutland
In stackleak_erase() we check skip_erasing() after accessing some fields from current. As generating the address of current uses asm which hazards with the static branch asm, this work is always performed, even when the static branch is patched to jump to the return at the end of the function. This patch avoids this redundant work by moving the skip_erasing() check earlier. To avoid complicating initialization within stackleak_erase(), the body of the function is split out into a __stackleak_erase() helper, with the check left in a wrapper function. The __stackleak_erase() helper is marked __always_inline to ensure that this is inlined into stackleak_erase() and not instrumented. Before this patch, on x86-64 w/ GCC 11.1.0 the start of the function is: <stackleak_erase>: 65 48 8b 04 25 00 00 mov %gs:0x0,%rax 00 00 48 8b 48 20 mov 0x20(%rax),%rcx 48 8b 80 98 0a 00 00 mov 0xa98(%rax),%rax 66 90 xchg %ax,%ax <------------ static branch 48 89 c2 mov %rax,%rdx 48 29 ca sub %rcx,%rdx 48 81 fa ff 3f 00 00 cmp $0x3fff,%rdx After this patch, on x86-64 w/ GCC 11.1.0 the start of the function is: <stackleak_erase>: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) <--- static branch 65 48 8b 04 25 00 00 mov %gs:0x0,%rax 00 00 48 8b 48 20 mov 0x20(%rax),%rcx 48 8b 80 98 0a 00 00 mov 0xa98(%rax),%rax 48 89 c2 mov %rax,%rdx 48 29 ca sub %rcx,%rdx 48 81 fa ff 3f 00 00 cmp $0x3fff,%rdx Before this patch, on arm64 w/ GCC 11.1.0 the start of the function is: <stackleak_erase>: d503245f bti c d5384100 mrs x0, sp_el0 f9401003 ldr x3, [x0, #32] f9451000 ldr x0, [x0, #2592] d503201f nop <------------------------------- static branch d503233f paciasp cb030002 sub x2, x0, x3 d287ffe1 mov x1, #0x3fff eb01005f cmp x2, x1 After this patch, on arm64 w/ GCC 11.1.0 the start of the function is: <stackleak_erase>: d503245f bti c d503201f nop <------------------------------- static branch d503233f paciasp d5384100 mrs x0, sp_el0 f9401003 ldr x3, [x0, #32] d287ffe1 mov x1, #0x3fff f9451000 ldr x0, [x0, #2592] cb030002 sub x2, x0, x3 eb01005f cmp x2, x1 While this may not be a huge win on its own, moving the static branch will permit further optimization of the body of the function in subsequent patches. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Popov <alex.popov@linux.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220427173128.2603085-3-mark.rutland@arm.com
2022-05-08arm64: stackleak: fix current_top_of_stack()Mark Rutland
Due to some historical confusion, arm64's current_top_of_stack() isn't what the stackleak code expects. This could in theory result in a number of problems, and practically results in an unnecessary performance hit. We can avoid this by aligning the arm64 implementation with the x86 implementation. The arm64 implementation of current_top_of_stack() was added specifically for stackleak in commit: 0b3e336601b82c6a ("arm64: Add support for STACKLEAK gcc plugin") This was intended to be equivalent to the x86 implementation, but the implementation, semantics, and performance characteristics differ wildly: * On x86, current_top_of_stack() returns the top of the current task's task stack, regardless of which stack is in active use. The implementation accesses a percpu variable which the x86 entry code maintains, and returns the location immediately above the pt_regs on the task stack (above which x86 has some padding). * On arm64 current_top_of_stack() returns the top of the stack in active use (i.e. the one which is currently being used). The implementation checks the SP against a number of potentially-accessible stacks, and will BUG() if no stack is found. The core stackleak_erase() code determines the upper bound of stack to erase with: | if (on_thread_stack()) | boundary = current_stack_pointer; | else | boundary = current_top_of_stack(); On arm64 stackleak_erase() is always called on a task stack, and on_thread_stack() should always be true. On x86, stackleak_erase() is mostly called on a trampoline stack, and is sometimes called on a task stack. Currently, this results in a lot of unnecessary code being generated for arm64 for the impossible !on_thread_stack() case. Some of this is inlined, bloating stackleak_erase(), while portions of this are left out-of-line and permitted to be instrumented (which would be a functional problem if that code were reachable). As a first step towards improving this, this patch aligns arm64's implementation of current_top_of_stack() with x86's, always returning the top of the current task's stack. With GCC 11.1.0 this results in the bulk of the unnecessary code being removed, including all of the out-of-line instrumentable code. While I don't believe there's a functional problem in practice I've marked this as a fix since the semantic was clearly wrong, the fix itself is simple, and other code might rely upon this in future. Fixes: 0b3e336601b82c6a ("arm64: Add support for STACKLEAK gcc plugin") Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Popov <alex.popov@linux.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Kees Cook <keescook@chromium.org> Cc: Will Deacon <will@kernel.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220427173128.2603085-2-mark.rutland@arm.com
2022-05-08randstruct: Enable Clang supportKees Cook
Clang 15 will support randstruct via the -frandomize-layout-seed-file=... option. Update the Kconfig and Makefile to recognize this feature. Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: linux-kbuild@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220503205503.3054173-7-keescook@chromium.org
2022-05-08randstruct: Move seed generation into scripts/basic/Kees Cook
To enable Clang randstruct support, move the structure layout randomization seed generation out of scripts/gcc-plugins/ into scripts/basic/ so it happens early enough that it can be used by either compiler implementation. The gcc-plugin still builds its own header file, but now does so from the common "randstruct.seed" file. Cc: linux-hardening@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220503205503.3054173-6-keescook@chromium.org
2022-05-08randstruct: Split randstruct Makefile and CFLAGSKees Cook
To enable the new Clang randstruct implementation[1], move randstruct into its own Makefile and split the CFLAGS from GCC_PLUGINS_CFLAGS into RANDSTRUCT_CFLAGS. [1] https://reviews.llvm.org/D121556 Cc: linux-hardening@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220503205503.3054173-5-keescook@chromium.org
2022-05-08randstruct: Reorganize Kconfigs and attribute macrosKees Cook
In preparation for Clang supporting randstruct, reorganize the Kconfigs, move the attribute macros, and generalize the feature to be named CONFIG_RANDSTRUCT for on/off, CONFIG_RANDSTRUCT_FULL for the full randomization mode, and CONFIG_RANDSTRUCT_PERFORMANCE for the cache-line sized mode. Cc: linux-hardening@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220503205503.3054173-4-keescook@chromium.org
2022-05-08sancov: Split plugin build from plugin CFLAGSKees Cook
When the sancov_plugin is enabled, it gets added to gcc-plugin-y which is used to populate both GCC_PLUGIN (for building the plugin) and GCC_PLUGINS_CFLAGS (for enabling and options). Instead of adding sancov to both and then removing it from GCC_PLUGINS_CFLAGS, create a separate list, gcc-plugin-external-y, which is only added to GCC_PLUGIN. This will also be used by the coming randstruct build changes. Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: linux-kbuild@vger.kernel.org Cc: linux-hardening@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220503205503.3054173-3-keescook@chromium.org
2022-05-08netfs: Eliminate Clang randstruct warningKees Cook
Clang's structure layout randomization feature gets upset when it sees struct inode (which is randomized) cast to struct netfs_i_context. This is due to seeing the inode pointer as being treated as an array of inodes, rather than "something else, following struct inode". Since netfs can't use container_of() (since it doesn't know what the true containing struct is), it uses this direct offset instead. Adjust the code to better reflect what is happening: an arbitrary pointer is being adjusted and cast to something else: use a "void *" for the math. The resulting binary output is the same, but Clang no longer sees an unexpected cross-structure cast: In file included from ../fs/nfs/inode.c:50: In file included from ../fs/nfs/fscache.h:15: In file included from ../include/linux/fscache.h:18: ../include/linux/netfs.h:298:9: error: casting from randomized structure pointer type 'struct inode *' to 'struct netfs_i_context *' return (struct netfs_i_context *)(inode + 1); ^ 1 error generated. Cc: David Howells <dhowells@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220503205503.3054173-2-keescook@chromium.org Reviewed-by: Jeff Layton <jlayton@kernel.org> Link: https://lore.kernel.org/lkml/7562f8eccd7cc0e447becfe9912179088784e3b9.camel@kernel.org
2022-05-07docs: kdump: Update the crashkernel description for arm64Zhen Lei
Now arm64 has added support for "crashkernel=X,high" and "crashkernel=Y,low". Unlike x86, crash low memory is not allocated if "crashkernel=Y,low" is not specified. Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Acked-by: Baoquan He <bhe@redhat.com> Link: https://lore.kernel.org/r/20220506114402.365-7-thunder.leizhen@huawei.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-05-07of: Support more than one crash kernel regions for kexec -sZhen Lei
When "crashkernel=X,high" is used, there may be two crash regions: high=crashk_res and low=crashk_low_res. But now the syscall kexec_file_load() only add crashk_res into "linux,usable-memory-range", this may cause the second kernel to have no available dma memory. Fix it like kexec-tools does for option -c, add both 'high' and 'low' regions into the dtb. Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Acked-by: Rob Herring <robh@kernel.org> Acked-by: Baoquan He <bhe@redhat.com> Link: https://lore.kernel.org/r/20220506114402.365-6-thunder.leizhen@huawei.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-05-07of: fdt: Add memory for devices by DT property "linux,usable-memory-range"Chen Zhou
When reserving crashkernel in high memory, some low memory is reserved for crash dump kernel devices and never mapped by the first kernel. This memory range is advertised to crash dump kernel via DT property under /chosen, linux,usable-memory-range = <BASE1 SIZE1 [BASE2 SIZE2]> We reused the DT property linux,usable-memory-range and made the low memory region as the second range "BASE2 SIZE2", which keeps compatibility with existing user-space and older kdump kernels. Crash dump kernel reads this property at boot time and call memblock_add() to add the low memory region after memblock_cap_memory_range() has been called. Signed-off-by: Chen Zhou <chenzhou10@huawei.com> Co-developed-by: Zhen Lei <thunder.leizhen@huawei.com> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Reviewed-by: Rob Herring <robh@kernel.org> Tested-by: Dave Kleikamp <dave.kleikamp@oracle.com> Acked-by: Baoquan He <bhe@redhat.com> Link: https://lore.kernel.org/r/20220506114402.365-5-thunder.leizhen@huawei.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-05-07arm64: kdump: Reimplement crashkernel=XChen Zhou
There are following issues in arm64 kdump: 1. We use crashkernel=X to reserve crashkernel in DMA zone, which will fail when there is not enough low memory. 2. If reserving crashkernel above DMA zone, in this case, crash dump kernel will fail to boot because there is no low memory available for allocation. To solve these issues, introduce crashkernel=X,[high,low]. The "crashkernel=X,high" is used to select a region above DMA zone, and the "crashkernel=Y,low" is used to allocate specified size low memory. Signed-off-by: Chen Zhou <chenzhou10@huawei.com> Co-developed-by: Zhen Lei <thunder.leizhen@huawei.com> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Link: https://lore.kernel.org/r/20220506114402.365-4-thunder.leizhen@huawei.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-05-07arm64: Use insert_resource() to simplify codeZhen Lei
insert_resource() traverses the subtree layer by layer from the root node until a proper location is found. Compared with request_resource(), the parent node does not need to be determined in advance. In addition, move the insertion of node 'crashk_res' into function reserve_crashkernel() to make the associated code close together. Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Acked-by: John Donnelly <john.p.donnelly@oracle.com> Acked-by: Baoquan He <bhe@redhat.com> Link: https://lore.kernel.org/r/20220506114402.365-3-thunder.leizhen@huawei.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-05-07kdump: return -ENOENT if required cmdline option does not existZhen Lei
According to the current crashkernel=Y,low support in other ARCHes, it's an optional command-line option. When it doesn't exist, kernel will try to allocate minimum required memory below 4G automatically. However, __parse_crashkernel() returns '-EINVAL' for all error cases. It can't distinguish the nonexistent option from invalid option. Change __parse_crashkernel() to return '-ENOENT' for the nonexistent option case. With this change, crashkernel,low memory will take the default value if crashkernel=,low is not specified; while crashkernel reservation will fail and bail out if an invalid option is specified. Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Acked-by: Baoquan He <bhe@redhat.com> Link: https://lore.kernel.org/r/20220506114402.365-2-thunder.leizhen@huawei.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-05-07SUNRPC: Ensure that the gssproxy client can start in a connected stateTrond Myklebust
Ensure that the gssproxy client connects to the server from the gssproxy daemon process context so that the AF_LOCAL socket connection is done using the correct path and namespaces. Fixes: 1d658336b05f ("SUNRPC: Add RPC based upcall mechanism for RPCGSS auth") Cc: stable@vger.kernel.org Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-05-07Revert "SUNRPC: Ensure gss-proxy connects on setup"Trond Myklebust
This reverts commit 892de36fd4a98fab3298d417c051d9099af5448d. The gssproxy server is unresponsive when it calls into the kernel to start the upcall service, so it will not reply to our RPC ping at all. Reported-by: "J.Bruce Fields" <bfields@fieldses.org> Fixes: 892de36fd4a9 ("SUNRPC: Ensure gss-proxy connects on setup") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-05-07Merge tag 'gpio-fixes-for-v5.18-rc6' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux Pull gpio fixes from Bartosz Golaszewski: - fix the bounds check for the 'gpio-reserved-ranges' device property in gpiolib-of - drop the assignment of the pwm base number in gpio-mvebu (this was missed by the patch doing it globally for all pwm drivers) - fix the fwnode assignment (use own fwnode, not the parent's one) for the GPIO irqchip in gpio-visconti - update the irq_stat field before checking the trigger field in gpio-pca953x - update GPIO entry in MAINTAINERS * tag 'gpio-fixes-for-v5.18-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux: gpio: pca953x: fix irq_stat not updated when irq is disabled (irq_mask not set) gpio: visconti: Fix fwnode of GPIO IRQ MAINTAINERS: update the GPIO git tree entry gpio: mvebu: drop pwm base assignment gpiolib: of: fix bounds check for 'gpio-reserved-ranges'
2022-05-07Merge tag 'block-5.18-2022-05-06' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block fixes from Jens Axboe: "A single revert for a change that isn't needed in 5.18, and a small series for s390/dasd" * tag 'block-5.18-2022-05-06' of git://git.kernel.dk/linux-block: s390/dasd: Use kzalloc instead of kmalloc/memset s390/dasd: Fix read inconsistency for ESE DASD devices s390/dasd: Fix read for ESE with blksize < 4k s390/dasd: prevent double format of tracks for ESE devices s390/dasd: fix data corruption for ESE devices Revert "block: release rq qos structures for queue without disk"
2022-05-07Merge tag 'io_uring-5.18-2022-05-06' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull io_uring fix from Jens Axboe: "Just a single file assignment fix this week" * tag 'io_uring-5.18-2022-05-06' of git://git.kernel.dk/linux-block: io_uring: assign non-fixed early for async work
2022-05-07fbdev: efifb: Fix a use-after-free due early fb_info cleanupJavier Martinez Canillas
Commit d258d00fb9c7 ("fbdev: efifb: Cleanup fb_info in .fb_destroy rather than .remove") attempted to fix a use-after-free error due driver freeing the fb_info in the .remove handler instead of doing it in .fb_destroy. But ironically that change introduced yet another use-after-free since the fb_info was still used after the free. This should fix for good by freeing the fb_info at the end of the handler. Fixes: d258d00fb9c7 ("fbdev: efifb: Cleanup fb_info in .fb_destroy rather than .remove") Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Reported-by: Andrzej Hajda <andrzej.hajda@intel.com> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com> Reviewed-by: Thomas Zimmermann <tzimemrmann@suse.de> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220506132225.588379-1-javierm@redhat.com
2022-05-06net: chelsio: cxgb4: Avoid potential negative array offsetKees Cook
Using min_t(int, ...) as a potential array index implies to the compiler that negative offsets should be allowed. This is not the case, though. Replace "int" with "unsigned int". Fixes the following warning exposed under future CONFIG_FORTIFY_SOURCE improvements: In file included from include/linux/string.h:253, from include/linux/bitmap.h:11, from include/linux/cpumask.h:12, from include/linux/smp.h:13, from include/linux/lockdep.h:14, from include/linux/rcupdate.h:29, from include/linux/rculist.h:11, from include/linux/pid.h:5, from include/linux/sched.h:14, from include/linux/delay.h:23, from drivers/net/ethernet/chelsio/cxgb4/t4_hw.c:35: drivers/net/ethernet/chelsio/cxgb4/t4_hw.c: In function 't4_get_raw_vpd_params': include/linux/fortify-string.h:46:33: warning: '__builtin_memcpy' pointer overflow between offset 29 and size [2147483648, 4294967295] [-Warray-bounds] 46 | #define __underlying_memcpy __builtin_memcpy | ^ include/linux/fortify-string.h:388:9: note: in expansion of macro '__underlying_memcpy' 388 | __underlying_##op(p, q, __fortify_size); \ | ^~~~~~~~~~~~~ include/linux/fortify-string.h:433:26: note: in expansion of macro '__fortify_memcpy_chk' 433 | #define memcpy(p, q, s) __fortify_memcpy_chk(p, q, s, \ | ^~~~~~~~~~~~~~~~~~~~ drivers/net/ethernet/chelsio/cxgb4/t4_hw.c:2796:9: note: in expansion of macro 'memcpy' 2796 | memcpy(p->id, vpd + id, min_t(int, id_len, ID_LEN)); | ^~~~~~ include/linux/fortify-string.h:46:33: warning: '__builtin_memcpy' pointer overflow between offset 0 and size [2147483648, 4294967295] [-Warray-bounds] 46 | #define __underlying_memcpy __builtin_memcpy | ^ include/linux/fortify-string.h:388:9: note: in expansion of macro '__underlying_memcpy' 388 | __underlying_##op(p, q, __fortify_size); \ | ^~~~~~~~~~~~~ include/linux/fortify-string.h:433:26: note: in expansion of macro '__fortify_memcpy_chk' 433 | #define memcpy(p, q, s) __fortify_memcpy_chk(p, q, s, \ | ^~~~~~~~~~~~~~~~~~~~ drivers/net/ethernet/chelsio/cxgb4/t4_hw.c:2798:9: note: in expansion of macro 'memcpy' 2798 | memcpy(p->sn, vpd + sn, min_t(int, sn_len, SERNUM_LEN)); | ^~~~~~ Additionally remove needless cast from u8[] to char * in last strim() call. Reported-by: kernel test robot <lkp@intel.com> Link: https://lore.kernel.org/lkml/202205031926.FVP7epJM-lkp@intel.com Fixes: fc9279298e3a ("cxgb4: Search VPD with pci_vpd_find_ro_info_keyword()") Fixes: 24c521f81c30 ("cxgb4: Use pci_vpd_find_id_string() to find VPD ID string") Cc: Raju Rangoju <rajur@chelsio.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220505233101.1224230-1-keescook@chromium.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-05-06netlink: do not reset transport header in netlink_recvmsg()Eric Dumazet
netlink_recvmsg() does not need to change transport header. If transport header was needed, it should have been reset by the producer (netlink_dump()), not the consumer(s). The following trace probably happened when multiple threads were using MSG_PEEK. BUG: KCSAN: data-race in netlink_recvmsg / netlink_recvmsg write to 0xffff88811e9f15b2 of 2 bytes by task 32012 on cpu 1: skb_reset_transport_header include/linux/skbuff.h:2760 [inline] netlink_recvmsg+0x1de/0x790 net/netlink/af_netlink.c:1978 sock_recvmsg_nosec net/socket.c:948 [inline] sock_recvmsg net/socket.c:966 [inline] __sys_recvfrom+0x204/0x2c0 net/socket.c:2097 __do_sys_recvfrom net/socket.c:2115 [inline] __se_sys_recvfrom net/socket.c:2111 [inline] __x64_sys_recvfrom+0x74/0x90 net/socket.c:2111 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae write to 0xffff88811e9f15b2 of 2 bytes by task 32005 on cpu 0: skb_reset_transport_header include/linux/skbuff.h:2760 [inline] netlink_recvmsg+0x1de/0x790 net/netlink/af_netlink.c:1978 ____sys_recvmsg+0x162/0x2f0 ___sys_recvmsg net/socket.c:2674 [inline] __sys_recvmsg+0x209/0x3f0 net/socket.c:2704 __do_sys_recvmsg net/socket.c:2714 [inline] __se_sys_recvmsg net/socket.c:2711 [inline] __x64_sys_recvmsg+0x42/0x50 net/socket.c:2711 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0xffff -> 0x0000 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 32005 Comm: syz-executor.4 Not tainted 5.18.0-rc1-syzkaller-00328-ge1f700ebd6be-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Link: https://lore.kernel.org/r/20220505161946.2867638-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-05-06drm/nouveau: Fix a potential theorical leak in nouveau_get_backlight_name()Christophe JAILLET
If successful ida_simple_get() calls are not undone when needed, some additional memory may be allocated and wasted. Here, an ID between 0 and MAX_INT is required. If this ID is >=100, it is not taken into account and is wasted. It should be released. Instead of calling ida_simple_remove(), take advantage of the 'max' parameter to require the ID not to be too big. Should it be too big, it is not allocated and don't need to be freed. While at it, use ida_alloc_xxx()/ida_free() instead to ida_simple_get()/ida_simple_remove(). The latter is deprecated and more verbose. Fixes: db1a0ae21461 ("drm/nouveau/bl: Assign different names to interfaces") Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Reviewed-by: Lyude Paul <lyude@redhat.com> [Fixed formatting warning from checkpatch] Signed-off-by: Lyude Paul <lyude@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/9ba85bca59df6813dc029e743a836451d5173221.1644386541.git.christophe.jaillet@wanadoo.fr
2022-05-06Merge tag 'for-5.18-rc5-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux Pull btrfs fixes from David Sterba: "Regression fixes in zone activation: - move a loop invariant out of the loop to avoid checking space status - properly handle unlimited activation Other fixes: - for subpage, force the free space v2 mount to avoid a warning and make it easy to switch a filesystem on different page size systems - export sysfs status of exclusive operation 'balance paused', so the user space tools can recognize it and allow adding a device with paused balance - fix assertion failure when logging directory key range item" * tag 'for-5.18-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: sysfs: export the balance paused state of exclusive operation btrfs: fix assertion failure when logging directory key range item btrfs: zoned: activate block group properly on unlimited active zone device btrfs: zoned: move non-changing condition check out of the loop btrfs: force v2 space cache usage for subpage mount
2022-05-06drm/nouveau/tegra: Stop using iommu_present()Robin Murphy
Even if some IOMMU has registered itself on the platform "bus", that doesn't necessarily mean it provides translation for the device we care about. Replace iommu_present() with a more appropriate check. Signed-off-by: Robin Murphy <robin.murphy@arm.com> Reviewed-by: Lyude Paul <lyude@redhat.com> [added cc for stable] Signed-off-by: Lyude Paul <lyude@redhat.com> Cc: stable@vger.kernel.org # v5.0+ Link: https://patchwork.freedesktop.org/patch/msgid/70d40ea441da3663c2824d54102b471e9a621f8a.1649168494.git.robin.murphy@arm.com
2022-05-06objtool: Fix STACK_FRAME_NON_STANDARD reloc typePeter Zijlstra
STACK_FRAME_NON_STANDARD results in inconsistent relocation types depending on .c or .S usage: Relocation section '.rela.discard.func_stack_frame_non_standard' at offset 0x3c01090 contains 5 entries: Offset Info Type Symbol's Value Symbol's Name + Addend 0000000000000000 00020c2200000002 R_X86_64_PC32 0000000000047b40 do_suspend_lowlevel + 0 0000000000000008 0002461e00000001 R_X86_64_64 00000000000480a0 machine_real_restart + 0 0000000000000010 0000001400000001 R_X86_64_64 0000000000000000 .rodata + b3d4 0000000000000018 0002444600000002 R_X86_64_PC32 00000000000678a0 __efi64_thunk + 0 0000000000000020 0002659d00000001 R_X86_64_64 0000000000113160 __crash_kexec + 0 Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220506121631.508692613@infradead.org
2022-05-06Merge tag 'nfs-for-5.18-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfsLinus Torvalds
Pull NFS client fixes from Trond Myklebust: "Highlights include: Stable fixes: - Fix a socket leak when setting up an AF_LOCAL RPC client - Ensure that knfsd connects to the gss-proxy daemon on setup Bugfixes: - Fix a refcount leak when migrating a task off an offlined transport - Don't gratuitously invalidate inode attributes on delegation return - Don't leak sockets in xs_local_connect() - Ensure timely close of disconnected AF_LOCAL sockets" * tag 'nfs-for-5.18-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: Revert "SUNRPC: attempt AF_LOCAL connect on setup" SUNRPC: Ensure gss-proxy connects on setup SUNRPC: Ensure timely close of disconnected AF_LOCAL sockets SUNRPC: Don't leak sockets in xs_local_connect() NFSv4: Don't invalidate inode attributes on delegation return SUNRPC release the transport of a relocated task with an assigned transport
2022-05-06ipv4: drop dst in multicast routing pathLokesh Dhoundiyal
kmemleak reports the following when routing multicast traffic over an ipsec tunnel. Kmemleak output: unreferenced object 0x8000000044bebb00 (size 256): comm "softirq", pid 0, jiffies 4294985356 (age 126.810s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 80 00 00 00 05 13 74 80 ..............t. 80 00 00 00 04 9b bf f9 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000f83947e0>] __kmalloc+0x1e8/0x300 [<00000000b7ed8dca>] metadata_dst_alloc+0x24/0x58 [<0000000081d32c20>] __ipgre_rcv+0x100/0x2b8 [<00000000824f6cf1>] gre_rcv+0x178/0x540 [<00000000ccd4e162>] gre_rcv+0x7c/0xd8 [<00000000c024b148>] ip_protocol_deliver_rcu+0x124/0x350 [<000000006a483377>] ip_local_deliver_finish+0x54/0x68 [<00000000d9271b3a>] ip_local_deliver+0x128/0x168 [<00000000bd4968ae>] xfrm_trans_reinject+0xb8/0xf8 [<0000000071672a19>] tasklet_action_common.isra.16+0xc4/0x1b0 [<0000000062e9c336>] __do_softirq+0x1fc/0x3e0 [<00000000013d7914>] irq_exit+0xc4/0xe0 [<00000000a4d73e90>] plat_irq_dispatch+0x7c/0x108 [<000000000751eb8e>] handle_int+0x16c/0x178 [<000000001668023b>] _raw_spin_unlock_irqrestore+0x1c/0x28 The metadata dst is leaked when ip_route_input_mc() updates the dst for the skb. Commit f38a9eb1f77b ("dst: Metadata destinations") correctly handled dropping the dst in ip_route_input_slow() but missed the multicast case which is handled by ip_route_input_mc(). Drop the dst in ip_route_input_mc() avoiding the leak. Fixes: f38a9eb1f77b ("dst: Metadata destinations") Signed-off-by: Lokesh Dhoundiyal <lokesh.dhoundiyal@alliedtelesis.co.nz> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://lore.kernel.org/r/20220505020017.3111846-1-chris.packham@alliedtelesis.co.nz Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-05-06s390/compat: cleanup compat_linux.h header fileHeiko Carstens
Remove various declarations from former s390 specific compat system calls which have been removed with commit fef747bab3c0 ("s390: use generic UID16 implementation"). While at it clean up the whole small header file. Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2022-05-06s390/entry: remove broken and not needed codeHeiko Carstens
LLVM's integrated assembler reports the following error when compiling entry.S: <instantiation>:38:5: error: unknown token in expression tm %r8,0x0001 # coming from user space? The correct instruction would have been tmhh instead of tm. The current code is doing nothing, since (with gas) it get's translated to a tm instruction which reads from real address 8, which again contains always zero, and therefore the conditional code is never executed. Note that due to the missing displacement gas translates "%r8" into "8(%r0)". Also code inspection reveals that this conditional code is not needed. Therefore remove it. Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2022-05-06s390/boot: convert parmarea to CHeiko Carstens
Convert parmarea to C, which makes it much easier to initialize it. No need to keep offsets in assembler code in sync with struct parmarea anymore. Reviewed-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2022-05-06s390/boot: convert initial lowcore to CHeiko Carstens
Convert initial lowcore to C and use proper defines and structures to initialize it. This should make the z/VM ipl procedure a bit less magic. Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com> Reviewed-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2022-05-06s390/ptrace: move short psw definitions to ptrace header fileHeiko Carstens
The short psw definitions are contained in compat header files, however short psws are not compat specific. Therefore move the definitions to ptrace header file. This also gets rid of a compat header include in kvm code. Acked-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2022-05-06s390/head: initialize all new pswsHeiko Carstens
Initialize all new psws with disabled wait psws, except for the restart new psw. This way every unexpected exception, svc, machine check, or interrupt is handled properly. Reviewed-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2022-05-06s390/boot: change initial program check handler to disabled wait pswHeiko Carstens
The program check handler of the kernel image points to startup_pgm_check_handler. However an early program check which happens while loading the kernel image will jump to potentially random code, since the code of the program check handler is not yet loaded; leading to a program check loop. Therefore initialize it to a disabled wait psw and let the startup code set the proper psw when everything is in memory. Reviewed-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2022-05-06s390/head: adjust iplstart entry pointHeiko Carstens
Move iplstart entry point to 0x200 again, instead of the middle of the ipl code. This way even the comment describing the ccw program is correct again. Acked-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2022-05-06s390/boot: get rid of startup archiveHeiko Carstens
The final kernel image is created by linking decompressor object files with a startup archive. The startup archive file however does not contain only optional code and data which can be discarded if not referenced. It also contains mandatory object data like head.o which must never be discarded, even if not referenced. Move the decompresser code and linker script to the boot directory and get rid of the startup archive so everything is kept during link time. Acked-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2022-05-06s390/vx: remove comments from macros which break LLVM's IASHeiko Carstens
LLVM's integrated assembler does not like comments within macros: <instantiation>:3:19: error: too many positional arguments GR_NUM b2, 1 /* Base register */ ^ Remove them, since they are obvious anyway. Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2022-05-06s390/extable: prefer local labels in .set directivesHeiko Carstens
Use local labels in .set directives to avoid potential compile errors with LTO + clang. See commit 334865b2915c ("x86/extable: Prefer local labels in .set directives") for further details. Since s390 doesn't support LTO currently this doesn't fix a real bug for now, but helps to avoid problems as soon as required pieces have been added to llvm. Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2022-05-06s390/nospec: prefer local labels in .set directivesHeiko Carstens
Use local labels in .set directives to avoid potential compile errors with LTO + clang. See commit 334865b2915c ("x86/extable: Prefer local labels in .set directives") for further details. Since s390 doesn't support LTO currently this doesn't fix a real bug for now, but helps to avoid problems as soon as required pieces have been added to llvm. Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2022-05-06s390/hypfs: fix typos in commentsJulia Lawall
Various spelling mistakes in comments. Detected with the help of Coccinelle. Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr> Link: https://lore.kernel.org/r/20220430191122.8667-5-Julia.Lawall@inria.fr Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2022-05-06s390/crypto: fix typos in commentsJulia Lawall
Various spelling mistakes in comments. Detected with the help of Coccinelle. Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr> Link: https://lore.kernel.org/r/20220430191122.8667-2-Julia.Lawall@inria.fr Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2022-05-06s390/consoles: improve panic notifiers reliabilityGuilherme G. Piccoli
Currently many console drivers for s390 rely on panic/reboot notifiers to invoke callbacks on these events. The panic() function disables local IRQs, secondary CPUs and preemption, so callbacks invoked on panic are effectively running in atomic context. Happens that most of these console callbacks from s390 doesn't take the proper care with regards to atomic context, like taking spinlocks that might be taken in other function/CPU and hence will cause a lockup situation. The goal for this patch is to improve the notifiers reliability, acting on 4 console drivers, as detailed below: (1) con3215: changed a regular spinlock to the trylock alternative. (2) con3270: also changed a regular spinlock to its trylock counterpart, but here we also have another problem: raw3270_activate_view() takes a different spinlock. So, we worked a helper to validate if this other lock is safe to acquire, and if so, raw3270_activate_view() should be safe. Notice though that there is a functional change here: it's now possible to continue the notifier code [reaching con3270_wait_write() and con3270_rebuild_update()] without executing raw3270_activate_view(). (3) sclp: a global lock is used heavily in the functions called from the notifier, so we added a check here - if the lock is taken already, we just bail-out, preventing the lockup. (4) sclp_vt220: same as (3), a lock validation was added to prevent the potential lockup problem. Besides (1)-(4), we also removed useless void functions, adding the code called from the notifier inside its own body, and changed the priority of such notifiers to execute late, since they are "heavyweight" for the panic environment, so we aim to reduce risks here. Changed return values to NOTIFY_DONE as well, the standard one. Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com> Link: https://lore.kernel.org/r/20220427224924.592546-14-gpiccoli@igalia.com Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2022-05-06Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull kvm fixes from Paolo Bonzini: "x86: - Account for family 17h event renumberings in AMD PMU emulation - Remove CPUID leaf 0xA on AMD processors - Fix lockdep issue with locking all vCPUs - Fix loss of A/D bits in SPTEs - Fix syzkaller issue with invalid guest state" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: KVM: VMX: Exit to userspace if vCPU has injected exception and invalid state KVM: SEV: Mark nested locking of vcpu->lock kvm: x86/cpuid: Only provide CPUID leaf 0xA if host has architectural PMU KVM: x86/svm: Account for family 17h event renumberings in amd_pmc_perf_hw_id KVM: x86/mmu: Use atomic XCHG to write TDP MMU SPTEs with volatile bits KVM: x86/mmu: Move shadow-present check out of spte_has_volatile_bits() KVM: x86/mmu: Don't treat fully writable SPTEs as volatile (modulo A/D)
2022-05-06Merge tag 'riscv-for-linus-5.18-rc6' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux Pull RISC-V fix from Palmer Dabbelt: - A fix to relocate the DTB early in boot, in cases where the bootloader doesn't put the DTB in a region that will end up mapped by the kernel. This manifests as a crash early in boot on a handful of configurations. * tag 'riscv-for-linus-5.18-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: RISC-V: relocate DTB if it's outside memory region
2022-05-06arm64/sme: More sensibly define the size for the ZA register setMark Brown
Since the vector length configuration mechanism is identical between SVE and SME we share large elements of the code including the definition for the maximum vector length. Unfortunately when we were defining the ABI for SVE we included not only the actual maximum vector length of 2048 bits but also the value possible if all the bits reserved in the architecture for expansion of the LEN field were used, 16384 bits. This starts creating problems if we try to allocate anything for the ZA matrix based on the maximum possible vector length, as we do for the regset used with ptrace during the process of generating a core dump. While the maximum potential size for ZA with the current architecture is a reasonably managable 64K with the higher reserved limit ZA would be 64M which leads to entirely reasonable complaints from the memory management code when we try to allocate a buffer of that size. Avoid these issues by defining the actual maximum vector length for the architecture and using it for the SME regsets. Also use the full ZA_PT_SIZE() with the header rather than just the actual register payload when specifying the size, fixing support for the largest vector lengths now that we have this new, lower define. With the SVE maximum this did not cause problems due to the extra headroom we had. While we're at it add a comment clarifying why even though ZA is a single register we tell the regset code that it is a multi-register regset. Reported-by: Qian Cai <quic_qiancai@quicinc.com> Signed-off-by: Mark Brown <broonie@kernel.org> Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org> Link: https://lore.kernel.org/r/20220505221517.1642014-1-broonie@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>