1. 05 May, 2020 11 commits
    • Aneesh Kumar K.V's avatar
      powerpc/kvm/book3s: Add helper to walk partition scoped linux page table. · 4b99412e
      Aneesh Kumar K.V authored
      The locking rules for walking partition scoped table is different from process
      scoped table. Hence add a helper for secondary linux page table walk and also
      add check whether we are holding the right locks.
      Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      Link: https://lore.kernel.org/r/20200505071729.54912-10-aneesh.kumar@linux.ibm.com
      4b99412e
    • Aneesh Kumar K.V's avatar
      powerpc/kvm/book3s: switch from raw_spin_*lock to arch_spin_lock. · 87013f9c
      Aneesh Kumar K.V authored
      These functions can get called in realmode. Hence use low level
      arch_spin_lock which is safe to be called in realmode.
      Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      Link: https://lore.kernel.org/r/20200505071729.54912-9-aneesh.kumar@linux.ibm.com
      87013f9c
    • Aneesh Kumar K.V's avatar
      powerpc/perf/callchain: Use __get_user_pages_fast in read_user_stack_slow · 15759cb0
      Aneesh Kumar K.V authored
      read_user_stack_slow is called with interrupts soft disabled and it copies contents
      from the page which we find mapped to a specific address. To convert
      userspace address to pfn, the kernel now uses lockless page table walk.
      
      The kernel needs to make sure the pfn value read remains stable and is not released
      and reused for another process while the contents are read from the page. This
      can only be achieved by holding a page reference.
      
      One of the first approaches I tried was to check the pte value after the kernel
      copies the contents from the page. But as shown below we can still get it wrong
      
      CPU0                           CPU1
      pte = READ_ONCE(*ptep);
                                     pte_clear(pte);
                                     put_page(page);
                                     page = alloc_page();
                                     memcpy(page_address(page), "secret password", nr);
      memcpy(buf, kaddr + offset, nb);
                                     put_page(page);
                                     handle_mm_fault()
                                     page = alloc_page();
                                     set_pte(pte, page);
      if (pte_val(pte) != pte_val(*ptep))
      
      Hence switch to __get_user_pages_fast.
      Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      Link: https://lore.kernel.org/r/20200505071729.54912-8-aneesh.kumar@linux.ibm.com
      15759cb0
    • Aneesh Kumar K.V's avatar
      powerpc/mce: Don't reload pte val in addr_to_pfn · 0da81b65
      Aneesh Kumar K.V authored
      A lockless page table walk should be safe against parallel THP collapse, THP
      split and madvise(MADV_DONTNEED)/parallel fault. This patch makes sure kernel
      won't reload the pteval when checking for different conditions. The patch also added
      a check for pte_present to make sure the kernel is indeed operating
      on a PTE and not a pointer to level 0 table page.
      
      The pfn value we find here can be different from the actual pfn on which
      machine check happened. This can happen if we raced with a parallel update
      of the page table. In such a scenario we end up isolating a wrong pfn. But that
      doesn't have any other side effect.
      Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      Link: https://lore.kernel.org/r/20200505071729.54912-7-aneesh.kumar@linux.ibm.com
      0da81b65
    • Aneesh Kumar K.V's avatar
      powerpc/book3s64/hash: Use the pte_t address from the caller · 2f92447f
      Aneesh Kumar K.V authored
      Don't fetch the pte value using lockless page table walk. Instead use the value from the
      caller. hash_preload is called with ptl lock held. So it is safe to use the
      pte_t address directly.
      Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      Link: https://lore.kernel.org/r/20200505071729.54912-6-aneesh.kumar@linux.ibm.com
      2f92447f
    • Aneesh Kumar K.V's avatar
      powerpc/hash64: Restrict page table lookup using init_mm with __flush_hash_table_range · 7900757c
      Aneesh Kumar K.V authored
      This is only used with init_mm currently. Walking init_mm is much simpler
      because we don't need to handle concurrent page table like other mm_context
      Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      Link: https://lore.kernel.org/r/20200505071729.54912-5-aneesh.kumar@linux.ibm.com
      7900757c
    • Aneesh Kumar K.V's avatar
      powerpc/mm/hash64: use _PAGE_PTE when checking for pte_present · ec4abf1e
      Aneesh Kumar K.V authored
      This makes the pte_present check stricter by checking for additional _PAGE_PTE
      bit. A level 1 pte pointer (THP pte) can be switched to a pointer to level 0 pte
      page table page by following two operations.
      
      1) THP split.
      2) madvise(MADV_DONTNEED) in parallel to page fault.
      
      A lockless page table walk need to make sure we can handle such changes
      gracefully.
      Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      Link: https://lore.kernel.org/r/20200505071729.54912-4-aneesh.kumar@linux.ibm.com
      ec4abf1e
    • Aneesh Kumar K.V's avatar
      powerpc/pkeys: Check vma before returning key fault error to the user · c46241a3
      Aneesh Kumar K.V authored
      If multiple threads in userspace keep changing the protection keys
      mapping a range, there can be a scenario where kernel takes a key fault
      but the pkey value found in the siginfo struct is a permissive one.
      
      This can confuse the userspace as shown in the below test case.
      
      /* use this to control the number of test iterations */
      
      static void pkeyreg_set(int pkey, unsigned long rights)
      {
      	unsigned long reg, shift;
      
      	shift = (NR_PKEYS - pkey - 1) * PKEY_BITS_PER_PKEY;
      	asm volatile("mfspr	%0, 0xd" : "=r"(reg));
      	reg &= ~(((unsigned long) PKEY_BITS_MASK) << shift);
      	reg |= (rights & PKEY_BITS_MASK) << shift;
      	asm volatile("mtspr	0xd, %0" : : "r"(reg));
      }
      
      static unsigned long pkeyreg_get(void)
      {
      	unsigned long reg;
      
      	asm volatile("mfspr	%0, 0xd" : "=r"(reg));
      	return reg;
      }
      
      static int sys_pkey_mprotect(void *addr, size_t len, int prot, int pkey)
      {
      	return syscall(SYS_pkey_mprotect, addr, len, prot, pkey);
      }
      
      static int sys_pkey_alloc(unsigned long flags, unsigned long access_rights)
      {
      	return syscall(SYS_pkey_alloc, flags, access_rights);
      }
      
      static int sys_pkey_free(int pkey)
      {
      	return syscall(SYS_pkey_free, pkey);
      }
      
      static int faulting_pkey;
      static int permissive_pkey;
      static pthread_barrier_t pkey_set_barrier;
      static pthread_barrier_t mprotect_barrier;
      
      static void pkey_handle_fault(int signum, siginfo_t *sinfo, void *ctx)
      {
      	unsigned long pkeyreg;
      
      	/* FIXME: printf is not signal-safe but for the current purpose,
      	          it gets the job done. */
      	printf("pkey: exp = %d, got = %d\n", faulting_pkey, sinfo->si_pkey);
      	fflush(stdout);
      
      	assert(sinfo->si_code == SEGV_PKUERR);
      	assert(sinfo->si_pkey == faulting_pkey);
      
      	/* clear pkey permissions to let the faulting instruction continue */
      	pkeyreg_set(faulting_pkey, 0x0);
      }
      
      static void *do_mprotect_fault(void *p)
      {
      	unsigned long rights, pkeyreg, pgsize;
      	unsigned int i;
      	void *region;
      	int pkey;
      
      	srand(time(NULL));
      	pgsize = sysconf(_SC_PAGESIZE);
      	rights = PKEY_DISABLE_WRITE;
      	region = p;
      
      	/* allocate key, no permissions */
      	assert((pkey = sys_pkey_alloc(0, PKEY_DISABLE_ACCESS)) > 0);
      	pkeyreg_set(4, 0x0);
      
      	/* cache the pkey here as the faulting pkey for future reference
      	   in the signal handler */
      	faulting_pkey = pkey;
      	printf("%s: faulting pkey = %d\n", __func__, faulting_pkey);
      
      	/* try to allocate, mprotect and free pkeys repeatedly */
      	for (i = 0; i < NUM_ITERATIONS; i++) {
      		/* sync up with the other thread here */
      		pthread_barrier_wait(&pkey_set_barrier);
      
      		/* make sure that the pkey used by the non-faulting thread
      		   is made permissive for this thread's context too so that
      		   no faults are triggered because it still might have been
      		   set to a restrictive value */
      //		pkeyreg_set(permissive_pkey, 0x0);
      
      		/* sync up with the other thread here */
      		pthread_barrier_wait(&mprotect_barrier);
      
      		/* perform mprotect */
      		assert(!sys_pkey_mprotect(region, pgsize, PROT_READ | PROT_WRITE, pkey));
      
      		/* choose a random byte from the protected region and
      		   attempt to write to it, this will generate a fault */
      		*((char *) region + (rand() % pgsize)) = rand();
      
      		/* restore pkey permissions as the signal handler may have
      		   cleared the bit out for the sake of continuing */
      		pkeyreg_set(pkey, PKEY_DISABLE_WRITE);
      	}
      
      	/* free pkey */
      	sys_pkey_free(pkey);
      
      	return NULL;
      }
      
      static void *do_mprotect_nofault(void *p)
      {
      	unsigned long pgsize;
      	unsigned int i, j;
      	void *region;
      	int pkey;
      
      	pgsize = sysconf(_SC_PAGESIZE);
      	region = p;
      
      	/* try to allocate, mprotect and free pkeys repeatedly */
      	for (i = 0; i < NUM_ITERATIONS; i++) {
      		/* allocate pkey, all permissions */
      		assert((pkey = sys_pkey_alloc(0, 0)) > 0);
      		permissive_pkey = pkey;
      
      		/* sync up with the other thread here */
      		pthread_barrier_wait(&pkey_set_barrier);
      		pthread_barrier_wait(&mprotect_barrier);
      
      		/* perform mprotect on the common page, no faults will
      		   be triggered as this is most permissive */
      		assert(!sys_pkey_mprotect(region, pgsize, PROT_READ | PROT_WRITE, pkey));
      
      		/* free pkey */
      		assert(!sys_pkey_free(pkey));
      	}
      
      	return NULL;
      }
      
      int main(int argc, char **argv)
      {
      	pthread_t fault_thread, nofault_thread;
      	unsigned long pgsize;
      	struct sigaction act;
      	pthread_attr_t attr;
      	cpu_set_t fault_cpuset, nofault_cpuset;
      	unsigned int i;
      	void *region;
      
      	/* allocate memory region to protect */
      	pgsize = sysconf(_SC_PAGESIZE);
      	assert(region = memalign(pgsize, pgsize));
      
      	CPU_ZERO(&fault_cpuset);
      	CPU_SET(0, &fault_cpuset);
      	CPU_ZERO(&nofault_cpuset);
      	CPU_SET(8, &nofault_cpuset);
      	assert(!pthread_attr_init(&attr));
      
      	/* setup sigsegv signal handler */
      	act.sa_handler = 0;
      	act.sa_sigaction = pkey_handle_fault;
      	assert(!sigprocmask(SIG_SETMASK, 0, &act.sa_mask));
      	act.sa_flags = SA_SIGINFO;
      	act.sa_restorer = 0;
      	assert(!sigaction(SIGSEGV, &act, NULL));
      
      	/* setup barrier for the two threads */
      	pthread_barrier_init(&pkey_set_barrier, NULL, 2);
      	pthread_barrier_init(&mprotect_barrier, NULL, 2);
      
      	/* setup and start threads */
      	assert(!pthread_create(&fault_thread, &attr, &do_mprotect_fault, region));
      	assert(!pthread_setaffinity_np(fault_thread, sizeof(cpu_set_t), &fault_cpuset));
      	assert(!pthread_create(&nofault_thread, &attr, &do_mprotect_nofault, region));
      	assert(!pthread_setaffinity_np(nofault_thread, sizeof(cpu_set_t), &nofault_cpuset));
      
      	/* cleanup */
      	assert(!pthread_attr_destroy(&attr));
      	assert(!pthread_join(fault_thread, NULL));
      	assert(!pthread_join(nofault_thread, NULL));
      	assert(!pthread_barrier_destroy(&pkey_set_barrier));
      	assert(!pthread_barrier_destroy(&mprotect_barrier));
      	free(region);
      
      	puts("PASS");
      
      	return EXIT_SUCCESS;
      }
      
      The above test can result the below failure without this patch.
      
      pkey: exp = 3, got = 3
      pkey: exp = 3, got = 4
      a.out: pkey-siginfo-race.c:100: pkey_handle_fault: Assertion `sinfo->si_pkey == faulting_pkey' failed.
      Aborted
      
      Check for vma access before considering this a key fault. If vma pkey allow
      access retry the acess again.
      
      Test case is written by Sandipan Das <sandipan@linux.ibm.com> hence added SOB
      from him.
      Signed-off-by: default avatarSandipan Das <sandipan@linux.ibm.com>
      Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      Link: https://lore.kernel.org/r/20200505071729.54912-3-aneesh.kumar@linux.ibm.com
      c46241a3
    • Aneesh Kumar K.V's avatar
      powerpc/pkeys: Avoid using lockless page table walk · fe4a6856
      Aneesh Kumar K.V authored
      Fetch pkey from vma instead of linux page table. Also document the fact that in
      some cases the pkey returned in siginfo won't be the same as the one we took
      keyfault on. Even with linux page table walk, we can end up in a similar scenario.
      Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      Link: https://lore.kernel.org/r/20200505071729.54912-2-aneesh.kumar@linux.ibm.com
      fe4a6856
    • Aneesh Kumar K.V's avatar
      mm: change pmdp_huge_get_and_clear_full take vm_area_struct as arg · 93a98695
      Aneesh Kumar K.V authored
      We will use this in later patch to do tlb flush when clearing pmd entries.
      Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      Link: https://lore.kernel.org/r/20200505071729.54912-22-aneesh.kumar@linux.ibm.com
      93a98695
    • Michael Ellerman's avatar
      Merge tag 'kvm-ppc-fixes-5.7-1' into topic/ppc-kvm · f2b8d76d
      Michael Ellerman authored
      This brings in a fix from the kvm-ppc tree that was merged to mainline
      after rc2, and so isn't in the base of our topic branch. We'd like it
      in the topic branch because it interacts with patches we plan to carry
      in this branch.
      f2b8d76d
  2. 20 Apr, 2020 1 commit
    • Paul Mackerras's avatar
      KVM: PPC: Book3S HV: Handle non-present PTEs in page fault functions · ae49deda
      Paul Mackerras authored
      Since cd758a9b "KVM: PPC: Book3S HV: Use __gfn_to_pfn_memslot in HPT
      page fault handler", it's been possible in fairly rare circumstances to
      load a non-present PTE in kvmppc_book3s_hv_page_fault() when running a
      guest on a POWER8 host.
      
      Because that case wasn't checked for, we could misinterpret the non-present
      PTE as being a cache-inhibited PTE.  That could mismatch with the
      corresponding hash PTE, which would cause the function to fail with -EFAULT
      a little further down.  That would propagate up to the KVM_RUN ioctl()
      generally causing the KVM userspace (usually qemu) to fall over.
      
      This addresses the problem by catching that case and returning to the guest
      instead.
      
      For completeness, this fixes the radix page fault handler in the same
      way.  For radix this didn't cause any obvious misbehaviour, because we
      ended up putting the non-present PTE into the guest's partition-scoped
      page tables, leading immediately to another hypervisor data/instruction
      storage interrupt, which would go through the page fault path again
      and fix things up.
      
      Fixes: cd758a9b "KVM: PPC: Book3S HV: Use __gfn_to_pfn_memslot in HPT page fault handler"
      Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1820402Reported-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
      Tested-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
      Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
      ae49deda
  3. 19 Apr, 2020 12 commits
    • Linus Torvalds's avatar
      Linux 5.7-rc2 · ae83d0b4
      Linus Torvalds authored
      ae83d0b4
    • Brian Geffon's avatar
      mm: Fix MREMAP_DONTUNMAP accounting on VMA merge · dadbd85f
      Brian Geffon authored
      When remapping a mapping where a portion of a VMA is remapped
      into another portion of the VMA it can cause the VMA to become
      split. During the copy_vma operation the VMA can actually
      be remerged if it's an anonymous VMA whose pages have not yet
      been faulted. This isn't normally a problem because at the end
      of the remap the original portion is unmapped causing it to
      become split again.
      
      However, MREMAP_DONTUNMAP leaves that original portion in place which
      means that the VMA which was split and then remerged is not actually
      split at the end of the mremap. This patch fixes a bug where
      we don't detect that the VMAs got remerged and we end up
      putting back VM_ACCOUNT on the next mapping which is completely
      unreleated. When that next mapping is unmapped it results in
      incorrectly unaccounting for the memory which was never accounted,
      and eventually we will underflow on the memory comittment.
      
      There is also another issue which is similar, we're currently
      accouting for the number of pages in the new_vma but that's wrong.
      We need to account for the length of the remap operation as that's
      all that is being added. If there was a mapping already at that
      location its comittment would have been adjusted as part of
      the munmap at the start of the mremap.
      
      A really simple repro can be seen in:
      https://gist.github.com/bgaff/e101ce99da7d9a8c60acc641d07f312c
      
      Fixes: e346b381 ("mm/mremap: add MREMAP_DONTUNMAP to mremap()")
      Reported-by: default avatarsyzbot <syzkaller@googlegroups.com>
      Signed-off-by: default avatarBrian Geffon <bgeffon@google.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      dadbd85f
    • Linus Torvalds's avatar
      Merge tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux · 86cc3398
      Linus Torvalds authored
      Pull clk fixes from Stephen Boyd:
       "Two build fixes for a couple clk drivers and a fix for the Unisoc
        serial clk where we want to keep it on for earlycon"
      
      * tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
        clk: sprd: don't gate uart console clock
        clk: mmp2: fix link error without mmp2
        clk: asm9260: fix __clk_hw_register_fixed_rate_with_accuracy typo
      86cc3398
    • Linus Torvalds's avatar
      Merge tag 'x86-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 0fe5f9ca
      Linus Torvalds authored
      Pull x86 and objtool fixes from Thomas Gleixner:
       "A set of fixes for x86 and objtool:
      
        objtool:
      
         - Ignore the double UD2 which is emitted in BUG() when
           CONFIG_UBSAN_TRAP is enabled.
      
         - Support clang non-section symbols in objtool ORC dump
      
         - Fix switch table detection in .text.unlikely
      
         - Make the BP scratch register warning more robust.
      
        x86:
      
         - Increase microcode maximum patch size for AMD to cope with new CPUs
           which have a larger patch size.
      
         - Fix a crash in the resource control filesystem when the removal of
           the default resource group is attempted.
      
         - Preserve Code and Data Prioritization enabled state accross CPU
           hotplug.
      
         - Update split lock cpu matching to use the new X86_MATCH macros.
      
         - Change the split lock enumeration as Intel finaly decided that the
           IA32_CORE_CAPABILITIES bits are not architectural contrary to what
           the SDM claims. !@#%$^!
      
         - Add Tremont CPU models to the split lock detection cpu match.
      
         - Add a missing static attribute to make sparse happy"
      
      * tag 'x86-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        x86/split_lock: Add Tremont family CPU models
        x86/split_lock: Bits in IA32_CORE_CAPABILITIES are not architectural
        x86/resctrl: Preserve CDP enable over CPU hotplug
        x86/resctrl: Fix invalid attempt at removing the default resource group
        x86/split_lock: Update to use X86_MATCH_INTEL_FAM6_MODEL()
        x86/umip: Make umip_insns static
        x86/microcode/AMD: Increase microcode PATCH_MAX_SIZE
        objtool: Make BP scratch register warning more robust
        objtool: Fix switch table detection in .text.unlikely
        objtool: Support Clang non-section symbols in ORC generation
        objtool: Support Clang non-section symbols in ORC dump
        objtool: Fix CONFIG_UBSAN_TRAP unreachable warnings
      0fe5f9ca
    • Linus Torvalds's avatar
      Merge tag 'timers-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 3e0dea57
      Linus Torvalds authored
      Pull time namespace fix from Thomas Gleixner:
       "An update for the proc interface of time namespaces: Use symbolic
        names instead of clockid numbers. The usability nuisance of numbers
        was noticed by Michael when polishing the man page"
      
      * tag 'timers-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        proc, time/namespace: Show clock symbolic names in /proc/pid/timens_offsets
      3e0dea57
    • Linus Torvalds's avatar
      Merge tag 'perf-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · b7374586
      Linus Torvalds authored
      Pull perf tooling fixes and updates from Thomas Gleixner:
      
       - Fix the header line of perf stat output for '--metric-only --per-socket'
      
       - Fix the python build with clang
      
       - The usual tools UAPI header synchronization
      
      * tag 'perf-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        tools headers: Synchronize linux/bits.h with the kernel sources
        tools headers: Adopt verbatim copy of compiletime_assert() from kernel sources
        tools headers: Update x86's syscall_64.tbl with the kernel sources
        tools headers UAPI: Sync drm/i915_drm.h with the kernel sources
        tools headers UAPI: Update tools's copy of drm.h headers
        tools headers kvm: Sync linux/kvm.h with the kernel sources
        tools headers UAPI: Sync linux/fscrypt.h with the kernel sources
        tools include UAPI: Sync linux/vhost.h with the kernel sources
        tools arch x86: Sync asm/cpufeatures.h with the kernel sources
        tools headers UAPI: Sync linux/mman.h with the kernel
        tools headers UAPI: Sync sched.h with the kernel
        tools headers: Update linux/vdso.h and grab a copy of vdso/const.h
        perf stat: Fix no metric header if --per-socket and --metric-only set
        perf python: Check if clang supports -fno-semantic-interposition
        tools arch x86: Sync the msr-index.h copy with the kernel sources
      b7374586
    • Linus Torvalds's avatar
      Merge tag 'irq-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 80ade29e
      Linus Torvalds authored
      Pull irq fixes from Thomas Gleixner:
       "A set of fixes/updates for the interrupt subsystem:
      
         - Remove setup_irq() and remove_irq(). All users have been converted
           so remove them before new users surface.
      
         - A set of bugfixes for various interrupt chip drivers
      
         - Add a few missing static attributes to address sparse warnings"
      
      * tag 'irq-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        irqchip/irq-bcm7038-l1: Make bcm7038_l1_of_init() static
        irqchip/irq-mvebu-icu: Make legacy_bindings static
        irqchip/meson-gpio: Fix HARDIRQ-safe -> HARDIRQ-unsafe lock order
        irqchip/sifive-plic: Fix maximum priority threshold value
        irqchip/ti-sci-inta: Fix processing of masked irqs
        irqchip/mbigen: Free msi_desc on device teardown
        irqchip/gic-v4.1: Update effective affinity of virtual SGIs
        irqchip/gic-v4.1: Add support for VPENDBASER's Dirty+Valid signaling
        genirq: Remove setup_irq() and remove_irq()
      80ade29e
    • Linus Torvalds's avatar
      Merge tag 'sched-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 08dd3872
      Linus Torvalds authored
      Pull scheduler fixes from Thomas Gleixner:
       "Two fixes for the scheduler:
      
         - Work around an uninitialized variable warning where GCC can't
           figure it out.
      
         - Allow 'isolcpus=' to skip unknown subparameters so that older
           kernels work with the commandline of a newer kernel. Improve the
           error output while at it"
      
      * tag 'sched-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        sched/vtime: Work around an unitialized variable warning
        sched/isolation: Allow "isolcpus=" to skip unknown sub-parameters
      08dd3872
    • Linus Torvalds's avatar
      Merge tag 'core-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 5e7de581
      Linus Torvalds authored
      Pull RCU fix from Thomas Gleixner:
       "A single bugfix for RCU to prevent taking a lock in NMI context"
      
      * tag 'core-urgent-2020-04-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        rcu: Don't acquire lock in NMI handler in rcu_nmi_enter_common()
      5e7de581
    • Linus Torvalds's avatar
      Merge tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 · 439f1da9
      Linus Torvalds authored
      Pull ext4 fixes from Ted Ts'o:
       "Miscellaneous bug fixes and cleanups for ext4, including a fix for
        generic/388 in data=journal mode, removing some BUG_ON's, and cleaning
        up some compiler warnings"
      
      * tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
        ext4: convert BUG_ON's to WARN_ON's in mballoc.c
        ext4: increase wait time needed before reuse of deleted inode numbers
        ext4: remove set but not used variable 'es' in ext4_jbd2.c
        ext4: remove set but not used variable 'es'
        ext4: do not zeroout extents beyond i_disksize
        ext4: fix return-value types in several function comments
        ext4: use non-movable memory for superblock readahead
        ext4: use matching invalidatepage in ext4_writepage
      439f1da9
    • Linus Torvalds's avatar
      Merge tag '5.7-rc-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6 · aee0314b
      Linus Torvalds authored
      Pull cifs fixes from Steve French:
       "Three small smb3 fixes: two debug related (helping network tracing for
        SMB2 mounts, and the other removing an unintended debug line on
        signing failures), and one fixing a performance problem with 64K
        pages"
      
      * tag '5.7-rc-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
        smb3: remove overly noisy debug line in signing errors
        cifs: improve read performance for page size 64KB & cache=strict & vers=2.1+
        cifs: dump the session id and keys also for SMB2 sessions
      aee0314b
    • Linus Torvalds's avatar
      Merge tag 'flexible-array-member-5.7-rc2' of... · 13402837
      Linus Torvalds authored
      Merge tag 'flexible-array-member-5.7-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux
      
      Pull flexible-array member conversion from Gustavo Silva:
       "The current codebase makes use of the zero-length array language
        extension to the C90 standard, but the preferred mechanism to declare
        variable-length types such as these ones is a flexible array
        member[1][2], introduced in C99:
      
          struct foo {
              int stuff;
              struct boo array[];
          };
      
        By making use of the mechanism above, we will get a compiler warning
        in case the flexible array does not occur last in the structure, which
        will help us prevent some kind of undefined behavior bugs from being
        inadvertently introduced[3] to the codebase from now on.
      
        Also, notice that, dynamic memory allocations won't be affected by
        this change:
      
         "Flexible array members have incomplete type, and so the sizeof
          operator may not be applied. As a quirk of the original
          implementation of zero-length arrays, sizeof evaluates to zero."[1]
      
        sizeof(flexible-array-member) triggers a warning because flexible
        array members have incomplete type[1]. There are some instances of
        code in which the sizeof operator is being incorrectly/erroneously
        applied to zero-length arrays and the result is zero. Such instances
        may be hiding some bugs. So, this work (flexible-array member
        convertions) will also help to get completely rid of those sorts of
        issues.
      
        Notice that all of these patches have been baking in linux-next for
        quite a while now and, 238 more of these patches have already been
        merged into 5.7-rc1.
      
        There are a couple hundred more of these issues waiting to be
        addressed in the whole codebase"
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      
      * tag 'flexible-array-member-5.7-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux: (28 commits)
        xattr.h: Replace zero-length array with flexible-array member
        uapi: linux: fiemap.h: Replace zero-length array with flexible-array member
        uapi: linux: dlm_device.h: Replace zero-length array with flexible-array member
        tpm_eventlog.h: Replace zero-length array with flexible-array member
        ti_wilink_st.h: Replace zero-length array with flexible-array member
        swap.h: Replace zero-length array with flexible-array member
        skbuff.h: Replace zero-length array with flexible-array member
        sched: topology.h: Replace zero-length array with flexible-array member
        rslib.h: Replace zero-length array with flexible-array member
        rio.h: Replace zero-length array with flexible-array member
        posix_acl.h: Replace zero-length array with flexible-array member
        platform_data: wilco-ec.h: Replace zero-length array with flexible-array member
        memcontrol.h: Replace zero-length array with flexible-array member
        list_lru.h: Replace zero-length array with flexible-array member
        lib: cpu_rmap: Replace zero-length array with flexible-array member
        irq.h: Replace zero-length array with flexible-array member
        ihex.h: Replace zero-length array with flexible-array member
        igmp.h: Replace zero-length array with flexible-array member
        genalloc.h: Replace zero-length array with flexible-array member
        ethtool.h: Replace zero-length array with flexible-array member
        ...
      13402837
  4. 18 Apr, 2020 16 commits
    • Linus Torvalds's avatar
      Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi · 50cc09c1
      Linus Torvalds authored
      Pull SCSI fixes from James Bottomley:
       "Seven fixes: three in target, one on a sg error leg, two in qla2xxx
        fixing warnings introduced in the last merge window and updating
        MAINTAINERS and one in hisi_sas fixing a problem introduced by libata"
      
      * tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
        scsi: sg: add sg_remove_request in sg_common_write
        scsi: target: tcmu: reset_ring should reset TCMU_DEV_BIT_BROKEN
        scsi: target: fix PR IN / READ FULL STATUS for FC
        scsi: target: Write NULL to *port_nexus_ptr if no ISID
        scsi: MAINTAINERS: Update qla2xxx FC-SCSI driver maintainer
        scsi: qla2xxx: Fix regression warnings
        scsi: hisi_sas: Fix build error without SATA_HOST
      50cc09c1
    • Gustavo A. R. Silva's avatar
      xattr.h: Replace zero-length array with flexible-array member · 43951585
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      43951585
    • Gustavo A. R. Silva's avatar
      uapi: linux: fiemap.h: Replace zero-length array with flexible-array member · 6e88abb8
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      6e88abb8
    • Gustavo A. R. Silva's avatar
      uapi: linux: dlm_device.h: Replace zero-length array with flexible-array member · d6cdad87
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      d6cdad87
    • Gustavo A. R. Silva's avatar
      tpm_eventlog.h: Replace zero-length array with flexible-array member · 06ccf63d
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      06ccf63d
    • Gustavo A. R. Silva's avatar
      ti_wilink_st.h: Replace zero-length array with flexible-array member · 4ea19ecf
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      4ea19ecf
    • Gustavo A. R. Silva's avatar
      swap.h: Replace zero-length array with flexible-array member · 16c3380f
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      16c3380f
    • Gustavo A. R. Silva's avatar
      skbuff.h: Replace zero-length array with flexible-array member · 5c91aa1d
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      5c91aa1d
    • Gustavo A. R. Silva's avatar
      sched: topology.h: Replace zero-length array with flexible-array member · fe946db6
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      fe946db6
    • Gustavo A. R. Silva's avatar
      rslib.h: Replace zero-length array with flexible-array member · 9dd8bb5f
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      9dd8bb5f
    • Gustavo A. R. Silva's avatar
      rio.h: Replace zero-length array with flexible-array member · a1c4b924
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      a1c4b924
    • Gustavo A. R. Silva's avatar
      posix_acl.h: Replace zero-length array with flexible-array member · 70f1451e
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      70f1451e
    • Gustavo A. R. Silva's avatar
      platform_data: wilco-ec.h: Replace zero-length array with flexible-array member · 1223f3db
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      1223f3db
    • Gustavo A. R. Silva's avatar
      memcontrol.h: Replace zero-length array with flexible-array member · 307ed94c
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      307ed94c
    • Gustavo A. R. Silva's avatar
      list_lru.h: Replace zero-length array with flexible-array member · 859b4941
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      859b4941
    • Gustavo A. R. Silva's avatar
      lib: cpu_rmap: Replace zero-length array with flexible-array member · 31232272
      Gustavo A. R. Silva authored
      The current codebase makes use of the zero-length array language
      extension to the C90 standard, but the preferred mechanism to declare
      variable-length types such as these ones is a flexible array member[1][2],
      introduced in C99:
      
      struct foo {
              int stuff;
              struct boo array[];
      };
      
      By making use of the mechanism above, we will get a compiler warning
      in case the flexible array does not occur last in the structure, which
      will help us prevent some kind of undefined behavior bugs from being
      inadvertently introduced[3] to the codebase from now on.
      
      Also, notice that, dynamic memory allocations won't be affected by
      this change:
      
      "Flexible array members have incomplete type, and so the sizeof operator
      may not be applied. As a quirk of the original implementation of
      zero-length arrays, sizeof evaluates to zero."[1]
      
      This issue was found with the help of Coccinelle.
      
      [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
      [2] https://github.com/KSPP/linux/issues/21
      [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
      Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
      31232272