BMC/Intel-BMC/linux.git/arch/s390/kernel, branch dev-5.15-intel

mm: defer kmemleak object creation of module_alloc()

2022-03-08T18:12:38+00:00

[ Upstream commit 60115fa54ad7b913b7cb5844e6b7ffeb842d55f2 ] Yongqiang reports a kmemleak panic when module insmod/rmmod with KASAN enabled(without KASAN_VMALLOC) on x86[1]. When the module area allocates memory, it's kmemleak_object is created successfully, but the KASAN shadow memory of module allocation is not ready, so when kmemleak scan the module's pointer, it will panic due to no shadow memory with KASAN check. module_alloc __vmalloc_node_range kmemleak_vmalloc kmemleak_scan update_checksum kasan_module_alloc kmemleak_ignore Note, there is no problem if KASAN_VMALLOC enabled, the modules area entire shadow memory is preallocated. Thus, the bug only exits on ARCH which supports dynamic allocation of module area per module load, for now, only x86/arm64/s390 are involved. Add a VM_DEFER_KMEMLEAK flags, defer vmalloc'ed object register of kmemleak in module_alloc() to fix this issue. [1] https://lore.kernel.org/all/6d41e2b9-4692-5ec4-b1cd-cbe29ae89739@huawei.com/ [wangkefeng.wang@huawei.com: fix build] Link: https://lkml.kernel.org/r/20211125080307.27225-1-wangkefeng.wang@huawei.com [akpm@linux-foundation.org: simplify ifdefs, per Andrey] Link: https://lkml.kernel.org/r/CA+fCnZcnwJHUQq34VuRxpdoY6_XbJCDJ-jopksS5Eia4PijPzw@mail.gmail.com Link: https://lkml.kernel.org/r/20211124142034.192078-1-wangkefeng.wang@huawei.com Fixes: 793213a82de4 ("s390/kasan: dynamic shadow mem allocation for modules") Fixes: 39d114ddc682 ("arm64: add KASAN support") Fixes: bebf56a1b176 ("kasan: enable instrumentation of global variables") Signed-off-by: Kefeng Wang Reported-by: Yongqiang Liu Cc: Andrey Konovalov Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Catalin Marinas Cc: Will Deacon Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Christian Borntraeger Cc: Alexander Gordeev Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: Alexander Potapenko Cc: Kefeng Wang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

s390/nmi: handle vector validity failures for KVM guests

2022-02-01T16:26:59+00:00

commit f094a39c6ba168f2df1edfd1731cca377af5f442 upstream. The machine check validity bit tells about the context. If a KVM guest was running the bit tells about the guest validity and the host state is not affected. As a guest can disable the guest validity this might result in unwanted host errors on machine checks. Cc: stable@vger.kernel.org Fixes: c929500d7a5a ("s390/nmi: s390: New low level handling for machine check happening in guest") Signed-off-by: Christian Borntraeger Reviewed-by: Heiko Carstens Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman

s390/nmi: handle guarded storage validity failures for KVM guests

2022-02-01T16:26:59+00:00

commit 1ea1d6a847d2b1d17fefd9196664b95f052a0775 upstream. machine check validity bits reflect the state of the machine check. If a guest does not make use of guarded storage, the validity bit might be off. We can not use the host CR bit to decide if the validity bit must be on. So ignore "invalid" guarded storage controls for KVM guests in the host and rely on the machine check being forwarded to the guest. If no other errors happen from a host perspective everything is fine and no process must be killed and the host can continue to run. Cc: stable@vger.kernel.org Fixes: c929500d7a5a ("s390/nmi: s390: New low level handling for machine check happening in guest") Reported-by: Carsten Otte Signed-off-by: Christian Borntraeger Tested-by: Carsten Otte Reviewed-by: Heiko Carstens Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman

s390/module: fix loading modules with a lot of relocations

2022-02-01T16:26:59+00:00

commit f3b7e73b2c6619884351a3a0a7468642f852b8a2 upstream. If the size of the PLT entries generated by apply_rela() exceeds 64KiB, the first ones can no longer reach __jump_r1 with brc. Fix by using brcl. An alternative solution is to add a __jump_r1 copy after every 64KiB, however, the space savings are quite small and do not justify the additional complexity. Fixes: f19fbd5ed642 ("s390: introduce execute-trampolines for branches") Cc: stable@vger.kernel.org Reported-by: Andrea Righi Signed-off-by: Ilya Leoshkevich Reviewed-by: Heiko Carstens Cc: Vasily Gorbik Cc: Christian Borntraeger Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman

s390/kexec: handle R_390_PLT32DBL rela in arch_kexec_apply_relocations_add()

2022-01-16T08:12:41+00:00

commit abf0e8e4ef25478a4390115e6a953d589d1f9ffd upstream. Starting with gcc 11.3, the C compiler will generate PLT-relative function calls even if they are local and do not require it. Later on during linking, the linker will replace all PLT-relative calls to local functions with PC-relative ones. Unfortunately, the purgatory code of kexec/kdump is not being linked as a regular executable or shared library would have been, and therefore, all PLT-relative addresses remain in the generated purgatory object code unresolved. This leads to the situation where the purgatory code is being executed during kdump with all PLT-relative addresses unresolved. And this results in endless loops within the purgatory code. Furthermore, the clang C compiler has always behaved like described above and this commit should fix kdump for kernels built with the latter. Because the purgatory code is no regular executable or shared library, contains only calls to local functions and has no PLT, all R_390_PLT32DBL relocation entries can be resolved just like a R_390_PC32DBL one. * https://refspecs.linuxfoundation.org/ELF/zSeries/lzsabi0_zSeries/x1633.html#AEN1699 Relocation entries of purgatory code generated with gcc 11.3 ------------------------------------------------------------ $ readelf -r linux/arch/s390/purgatory/purgatory.o Relocation section '.rela.text' at offset 0x370 contains 5 entries: Offset Info Type Sym. Value Sym. Name + Addend 00000000005c 000c00000013 R_390_PC32DBL 0000000000000000 purgatory_sha_regions + 2 00000000007a 000d00000014 R_390_PLT32DBL 0000000000000000 sha256_update + 2 00000000008c 000e00000014 R_390_PLT32DBL 0000000000000000 sha256_final + 2 000000000092 000800000013 R_390_PC32DBL 0000000000000000 .LC0 + 2 0000000000a0 000f00000014 R_390_PLT32DBL 0000000000000000 memcmp + 2 Relocation entries of purgatory code generated with gcc 11.2 ------------------------------------------------------------ $ readelf -r linux/arch/s390/purgatory/purgatory.o Relocation section '.rela.text' at offset 0x368 contains 5 entries: Offset Info Type Sym. Value Sym. Name + Addend 00000000005c 000c00000013 R_390_PC32DBL 0000000000000000 purgatory_sha_regions + 2 00000000007a 000d00000013 R_390_PC32DBL 0000000000000000 sha256_update + 2 00000000008c 000e00000013 R_390_PC32DBL 0000000000000000 sha256_final + 2 000000000092 000800000013 R_390_PC32DBL 0000000000000000 .LC0 + 2 0000000000a0 000f00000013 R_390_PC32DBL 0000000000000000 memcmp + 2 Signed-off-by: Alexander Egorenkov Reported-by: Tao Liu Suggested-by: Philipp Rudo Reviewed-by: Philipp Rudo Cc: Link: https://lore.kernel.org/r/20211209073817.82196-1-egorenar@linux.ibm.com Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman

s390/kexec_file: fix error handling when applying relocations

2021-12-22T08:32:40+00:00

[ Upstream commit 41967a37b8eedfee15b81406a9f3015be90d3980 ] arch_kexec_apply_relocations_add currently ignores all errors returned by arch_kexec_do_relocs. This means that every unknown relocation is silently skipped causing unpredictable behavior while the relocated code runs. Fix this by checking for errors and fail kexec_file_load if an unknown relocation type is encountered. The problem was found after gcc changed its behavior and used R_390_PLT32DBL relocations for brasl instruction and relied on ld to resolve the relocations in the final link in case direct calls are possible. As the purgatory code is only linked partially (option -r) ld didn't resolve the relocations leaving them for arch_kexec_do_relocs. But arch_kexec_do_relocs doesn't know how to handle R_390_PLT32DBL relocations so they were silently skipped. This ultimately caused an endless loop in the purgatory as the brasl instructions kept branching to itself. Fixes: 71406883fd35 ("s390/kexec_file: Add kexec_file_load system call") Reported-by: Tao Liu Signed-off-by: Philipp Rudo Link: https://lore.kernel.org/r/20211208130741.5821-3-prudo@redhat.com Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin

s390/entry: fix duplicate tracking of irq nesting level

2021-12-22T08:32:36+00:00

commit c9b12b59e2ea4c3c7cedec7efb071b649652f3a9 upstream. In the current code, when exiting from idle, rcu_irq_enter() is called twice during irq entry: irq_entry_enter()-> rcu_irq_enter() irq_enter() -> rcu_irq_enter() This may lead to wrong results from rcu_is_cpu_rrupt_from_idle() because of a wrong dynticks nmi nesting count. Fix this by only calling irq_enter_rcu(). Cc: # 5.12+ Reported-by: Mark Rutland Fixes: 56e62a737028 ("s390: convert to generic entry") Signed-off-by: Sven Schnelle Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman

s390/setup: avoid using memblock_enforce_memory_limit

2021-12-08T08:04:39+00:00

[ Upstream commit 5dbc4cb4667457b0c53bcd7bff11500b3c362975 ] There is a difference in how architectures treat "mem=" option. For some that is an amount of online memory, for s390 and x86 this is the limiting max address. Some memblock api like memblock_enforce_memory_limit() take limit argument and explicitly treat it as the size of online memory, and use __find_max_addr to convert it to an actual max address. Current s390 usage: memblock_enforce_memory_limit(memblock_end_of_DRAM()); yields different results depending on presence of memory holes (offline memory blocks in between online memory). If there are no memory holes limit == max_addr in memblock_enforce_memory_limit() and it does trim online memory and reserved memory regions. With memory holes present it actually does nothing. Since we already use memblock_remove() explicitly to trim online memory regions to potential limit (think mem=, kdump, addressing limits, etc.) drop the usage of memblock_enforce_memory_limit() altogether. Trimming reserved regions should not be required, since we now use memblock_set_current_limit() to limit allocations and any explicit memory reservations above the limit is an actual problem we should not hide. Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin

signal: Replace force_fatal_sig with force_exit_sig when in doubt

2021-11-25T08:49:07+00:00

commit fcb116bc43c8c37c052530ead79872f8b2615711 upstream. Recently to prevent issues with SECCOMP_RET_KILL and similar signals being changed before they are delivered SA_IMMUTABLE was added. Unfortunately this broke debuggers[1][2] which reasonably expect to be able to trap synchronous SIGTRAP and SIGSEGV even when the target process is not configured to handle those signals. Add force_exit_sig and use it instead of force_fatal_sig where historically the code has directly called do_exit. This has the implementation benefits of going through the signal exit path (including generating core dumps) without the danger of allowing userspace to ignore or change these signals. This avoids userspace regressions as older kernels exited with do_exit which debuggers also can not intercept. In the future is should be possible to improve the quality of implementation of the kernel by changing some of these force_exit_sig calls to force_fatal_sig. That can be done where it matters on a case-by-case basis with careful analysis. Reported-by: Kyle Huey Reported-by: kernel test robot [1] https://lkml.kernel.org/r/CAP045AoMY4xf8aC_4QU_-j7obuEPYgTcnQQP3Yxk=2X90jtpjw@mail.gmail.com [2] https://lkml.kernel.org/r/20211117150258.GB5403@xsang-OptiPlex-9020 Fixes: 00b06da29cf9 ("signal: Add SA_IMMUTABLE to ensure forced siganls do not get changed") Fixes: a3616a3c0272 ("signal/m68k: Use force_sigsegv(SIGSEGV) in fpsp040_die") Fixes: 83a1f27ad773 ("signal/powerpc: On swapcontext failure force SIGSEGV") Fixes: 9bc508cf0791 ("signal/s390: Use force_sigsegv in default_trap_handler") Fixes: 086ec444f866 ("signal/sparc32: In setup_rt_frame and setup_fram use force_fatal_sig") Fixes: c317d306d550 ("signal/sparc32: Exit with a fatal signal when try_to_clear_window_buffer fails") Fixes: 695dd0d634df ("signal/x86: In emulate_vsyscall force a signal instead of calling do_exit") Fixes: 1fbd60df8a85 ("signal/vm86_32: Properly send SIGSEGV when the vm86 state cannot be saved.") Fixes: 941edc5bf174 ("exit/syscall_user_dispatch: Send ordinary signals on failure") Link: https://lkml.kernel.org/r/871r3dqfv8.fsf_-_@email.froward.int.ebiederm.org Reviewed-by: Kees Cook Tested-by: Kees Cook Tested-by: Kyle Huey Signed-off-by: "Eric W. Biederman" Cc: Thomas Backlund Signed-off-by: Greg Kroah-Hartman

signal: Replace force_sigsegv(SIGSEGV) with force_fatal_sig(SIGSEGV)

2021-11-25T08:49:06+00:00

commit e21294a7aaae32c5d7154b187113a04db5852e37 upstream. Now that force_fatal_sig exists it is unnecessary and a bit confusing to use force_sigsegv in cases where the simpler force_fatal_sig is wanted. So change every instance we can to make the code clearer. Acked-by: Geert Uytterhoeven Reviewed-by: Philippe Mathieu-Daudé Link: https://lkml.kernel.org/r/877de7jrev.fsf@disp2133 Signed-off-by: "Eric W. Biederman" Cc: Thomas Backlund Signed-off-by: Greg Kroah-Hartman