Merge tag 'uninit-macro-v5.9-rc1' of git://git.kernel.org/pub/scm/lin…

…ux/kernel/git/kees/linux Pull uninitialized_var() macro removal from Kees Cook: "This is long overdue, and has hidden too many bugs over the years. The series has several "by hand" fixes, and then a trivial treewide replacement. - Clean up non-trivial uses of uninitialized_var() - Update documentation and checkpatch for uninitialized_var() removal - Treewide removal of uninitialized_var()" * tag 'uninit-macro-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: compiler: Remove uninitialized_var() macro treewide: Remove uninitialized_var() usage checkpatch: Remove awareness of uninitialized_var() macro mm/debug_vm_pgtable: Remove uninitialized_var() usage f2fs: Eliminate usage of uninitialized_var() macro media: sur40: Remove uninitialized_var() usage KVM: PPC: Book3S PR: Remove uninitialized_var() usage clk: spear: Remove uninitialized_var() usage clk: st: Remove uninitialized_var() usage spi: davinci: Remove uninitialized_var() usage ide: Remove uninitialized_var() usage rtlwifi: rtl8192cu: Remove uninitialized_var() usage b43: Remove uninitialized_var() usage drbd: Remove uninitialized_var() usage x86/mm/numa: Remove uninitialized_var() usage docs: deprecated.rst: Add uninitialized_var()
fracktal · Aug 4, 2020 · 99ea152 · 99ea152
2 parents 427714f + 63a0895
commit 99ea152
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diff --git a/Documentation/process/deprecated.rst b/Documentation/process/deprecated.rst
@@ -51,6 +51,24 @@ to make sure their systems do not continue running in the face of
 "unreachable" conditions. (For example, see commits like `this one
 <https://git.kernel.org/linus/d4689846881d160a4d12a514e991a740bcb5d65a>`_.)
 
+uninitialized_var()
+-------------------
+For any compiler warnings about uninitialized variables, just add
+an initializer. Using the uninitialized_var() macro (or similar
+warning-silencing tricks) is dangerous as it papers over `real bugs
+<https://lore.kernel.org/lkml/[email protected]/>`_
+(or can in the future), and suppresses unrelated compiler warnings
+(e.g. "unused variable"). If the compiler thinks it is uninitialized,
+either simply initialize the variable or make compiler changes. Keep in
+mind that in most cases, if an initialization is obviously redundant,
+the compiler's dead-store elimination pass will make sure there are no
+needless variable writes.
+
+As Linus has said, this macro
+`must <https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/>`_
+`be <https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/>`_
+`removed <https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/>`_.
+
 open-coded arithmetic in allocator arguments
 --------------------------------------------
 Dynamic size calculations (especially multiplication) should not be

diff --git a/arch/arm/mach-sa1100/assabet.c b/arch/arm/mach-sa1100/assabet.c
@@ -652,7 +652,7 @@ static void __init map_sa1100_gpio_regs( void )
  */
 static void __init get_assabet_scr(void)
 {
-	unsigned long uninitialized_var(scr), i;
+	unsigned long scr, i;
 
 	GPDR |= 0x3fc;			/* Configure GPIO 9:2 as outputs */
 	GPSR = 0x3fc;			/* Write 0xFF to GPIO 9:2 */

diff --git a/arch/arm/mm/alignment.c b/arch/arm/mm/alignment.c
@@ -799,7 +799,7 @@ static int alignment_get_thumb(struct pt_regs *regs, u16 *ip, u16 *inst)
 static int
 do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 {
-	union offset_union uninitialized_var(offset);
+	union offset_union offset;
 	unsigned long instrptr;
 	int (*handler)(unsigned long addr, u32 instr, struct pt_regs *regs);
 	unsigned int type;

diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
@@ -445,7 +445,7 @@ static void
 do_copy_task_regs (struct task_struct *task, struct unw_frame_info *info, void *arg)
 {
 	unsigned long mask, sp, nat_bits = 0, ar_rnat, urbs_end, cfm;
-	unsigned long uninitialized_var(ip);	/* GCC be quiet */
+	unsigned long ip;
 	elf_greg_t *dst = arg;
 	struct pt_regs *pt;
 	char nat;

diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c
@@ -180,7 +180,7 @@ static void *per_cpu_node_setup(void *cpu_data, int node)
 void __init setup_per_cpu_areas(void)
 {
 	struct pcpu_alloc_info *ai;
-	struct pcpu_group_info *uninitialized_var(gi);
+	struct pcpu_group_info *gi;
 	unsigned int *cpu_map;
 	void *base;
 	unsigned long base_offset;

diff --git a/arch/ia64/mm/tlb.c b/arch/ia64/mm/tlb.c
@@ -369,7 +369,7 @@ EXPORT_SYMBOL(flush_tlb_range);
 
 void ia64_tlb_init(void)
 {
-	ia64_ptce_info_t uninitialized_var(ptce_info); /* GCC be quiet */
+	ia64_ptce_info_t ptce_info;
 	u64 tr_pgbits;
 	long status;
 	pal_vm_info_1_u_t vm_info_1;

diff --git a/arch/mips/lib/dump_tlb.c b/arch/mips/lib/dump_tlb.c
@@ -79,7 +79,7 @@ static void dump_tlb(int first, int last)
 	unsigned int pagemask, guestctl1 = 0, c0, c1, i;
 	unsigned long asidmask = cpu_asid_mask(&current_cpu_data);
 	int asidwidth = DIV_ROUND_UP(ilog2(asidmask) + 1, 4);
-	unsigned long uninitialized_var(s_mmid);
+	unsigned long s_mmid;
 #ifdef CONFIG_32BIT
 	bool xpa = cpu_has_xpa && (read_c0_pagegrain() & PG_ELPA);
 	int pwidth = xpa ? 11 : 8;

diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
@@ -83,7 +83,7 @@ void setup_zero_pages(void)
 static void *__kmap_pgprot(struct page *page, unsigned long addr, pgprot_t prot)
 {
 	enum fixed_addresses idx;
-	unsigned int uninitialized_var(old_mmid);
+	unsigned int old_mmid;
 	unsigned long vaddr, flags, entrylo;
 	unsigned long old_ctx;
 	pte_t pte;

diff --git a/arch/mips/mm/tlb-r4k.c b/arch/mips/mm/tlb-r4k.c
@@ -119,7 +119,7 @@ void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 		if (size <= (current_cpu_data.tlbsizeftlbsets ?
 			     current_cpu_data.tlbsize / 8 :
 			     current_cpu_data.tlbsize / 2)) {
-			unsigned long old_entryhi, uninitialized_var(old_mmid);
+			unsigned long old_entryhi, old_mmid;
 			int newpid = cpu_asid(cpu, mm);
 
 			old_entryhi = read_c0_entryhi();
@@ -213,7 +213,7 @@ void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 	int cpu = smp_processor_id();
 
 	if (cpu_context(cpu, vma->vm_mm) != 0) {
-		unsigned long uninitialized_var(old_mmid);
+		unsigned long old_mmid;
 		unsigned long flags, old_entryhi;
 		int idx;
 
@@ -382,7 +382,7 @@ void add_wired_entry(unsigned long entrylo0, unsigned long entrylo1,
 #ifdef CONFIG_XPA
 	panic("Broken for XPA kernels");
 #else
-	unsigned int uninitialized_var(old_mmid);
+	unsigned int old_mmid;
 	unsigned long flags;
 	unsigned long wired;
 	unsigned long old_pagemask;

diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -33,7 +33,7 @@ unsigned long __kvmhv_copy_tofrom_guest_radix(int lpid, int pid,
 					      gva_t eaddr, void *to, void *from,
 					      unsigned long n)
 {
-	int uninitialized_var(old_pid), old_lpid;
+	int old_pid, old_lpid;
 	unsigned long quadrant, ret = n;
 	bool is_load = !!to;
 

diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
@@ -1828,9 +1828,6 @@ static int kvmppc_vcpu_run_pr(struct kvm_vcpu *vcpu)
 {
 	struct kvm_run *run = vcpu->run;
 	int ret;
-#ifdef CONFIG_ALTIVEC
-	unsigned long uninitialized_var(vrsave);
-#endif
 
 	/* Check if we can run the vcpu at all */
 	if (!vcpu->arch.sane) {

diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
@@ -1110,7 +1110,7 @@ static inline u32 dp_to_sp(u64 fprd)
 static void kvmppc_complete_mmio_load(struct kvm_vcpu *vcpu)
 {
 	struct kvm_run *run = vcpu->run;
-	u64 uninitialized_var(gpr);
+	u64 gpr;
 
 	if (run->mmio.len > sizeof(gpr)) {
 		printk(KERN_ERR "bad MMIO length: %d\n", run->mmio.len);

diff --git a/arch/powerpc/platforms/52xx/mpc52xx_pic.c b/arch/powerpc/platforms/52xx/mpc52xx_pic.c
@@ -340,7 +340,7 @@ static int mpc52xx_irqhost_map(struct irq_domain *h, unsigned int virq,
 {
 	int l1irq;
 	int l2irq;
-	struct irq_chip *uninitialized_var(irqchip);
+	struct irq_chip *irqchip;
 	void *hndlr;
 	int type;
 	u32 reg;

diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
@@ -146,7 +146,7 @@ static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
 
 static inline int pcpu_stopped(struct pcpu *pcpu)
 {
-	u32 uninitialized_var(status);
+	u32 status;
 
 	if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
 			0, &status) != SIGP_CC_STATUS_STORED)

diff --git a/arch/x86/kernel/quirks.c b/arch/x86/kernel/quirks.c
@@ -95,7 +95,7 @@ static void ich_force_hpet_resume(void)
 static void ich_force_enable_hpet(struct pci_dev *dev)
 {
 	u32 val;
-	u32 uninitialized_var(rcba);
+	u32 rcba;
 	int err = 0;
 
 	if (hpet_address || force_hpet_address)
@@ -185,7 +185,7 @@ static void hpet_print_force_info(void)
 static void old_ich_force_hpet_resume(void)
 {
 	u32 val;
-	u32 uninitialized_var(gen_cntl);
+	u32 gen_cntl;
 
 	if (!force_hpet_address || !cached_dev)
 		return;
@@ -207,7 +207,7 @@ static void old_ich_force_hpet_resume(void)
 static void old_ich_force_enable_hpet(struct pci_dev *dev)
 {
 	u32 val;
-	u32 uninitialized_var(gen_cntl);
+	u32 gen_cntl;
 
 	if (hpet_address || force_hpet_address)
 		return;
@@ -298,7 +298,7 @@ static void vt8237_force_hpet_resume(void)
 
 static void vt8237_force_enable_hpet(struct pci_dev *dev)
 {
-	u32 uninitialized_var(val);
+	u32 val;
 
 	if (hpet_address || force_hpet_address)
 		return;
@@ -429,7 +429,7 @@ static void nvidia_force_hpet_resume(void)
 
 static void nvidia_force_enable_hpet(struct pci_dev *dev)
 {
-	u32 uninitialized_var(val);
+	u32 val;
 
 	if (hpet_address || force_hpet_address)
 		return;

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
@@ -1986,7 +1986,7 @@ static int kvm_age_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
 			 unsigned long data)
 {
 	u64 *sptep;
-	struct rmap_iterator uninitialized_var(iter);
+	struct rmap_iterator iter;
 	int young = 0;
 
 	for_each_rmap_spte(rmap_head, &iter, sptep)

diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -314,7 +314,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,
 {
 	int ret;
 	pt_element_t pte;
-	pt_element_t __user *uninitialized_var(ptep_user);
+	pt_element_t __user *ptep_user;
 	gfn_t table_gfn;
 	u64 pt_access, pte_access;
 	unsigned index, accessed_dirty, pte_pkey;

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
@@ -9932,7 +9932,7 @@ void kvm_arch_sync_events(struct kvm *kvm)
 int __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size)
 {
 	int i, r;
-	unsigned long hva, uninitialized_var(old_npages);
+	unsigned long hva, old_npages;
 	struct kvm_memslots *slots = kvm_memslots(kvm);
 	struct kvm_memory_slot *slot;
 

diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
@@ -543,7 +543,6 @@ static void __init numa_clear_kernel_node_hotplug(void)
 
 static int __init numa_register_memblks(struct numa_meminfo *mi)
 {
-	unsigned long uninitialized_var(pfn_align);
 	int i, nid;
 
 	/* Account for nodes with cpus and no memory */
@@ -571,15 +570,16 @@ static int __init numa_register_memblks(struct numa_meminfo *mi)
 	 * If sections array is gonna be used for pfn -> nid mapping, check
 	 * whether its granularity is fine enough.
 	 */
-#ifdef NODE_NOT_IN_PAGE_FLAGS
-	pfn_align = node_map_pfn_alignment();
-	if (pfn_align && pfn_align < PAGES_PER_SECTION) {
-		printk(KERN_WARNING "Node alignment %LuMB < min %LuMB, rejecting NUMA config\n",
-		       PFN_PHYS(pfn_align) >> 20,
-		       PFN_PHYS(PAGES_PER_SECTION) >> 20);
-		return -EINVAL;
+	if (IS_ENABLED(NODE_NOT_IN_PAGE_FLAGS)) {
+		unsigned long pfn_align = node_map_pfn_alignment();
+
+		if (pfn_align && pfn_align < PAGES_PER_SECTION) {
+			pr_warn("Node alignment %LuMB < min %LuMB, rejecting NUMA config\n",
+				PFN_PHYS(pfn_align) >> 20,
+				PFN_PHYS(PAGES_PER_SECTION) >> 20);
+			return -EINVAL;
+		}
 	}
-#endif
 	if (!numa_meminfo_cover_memory(mi))
 		return -EINVAL;
 

diff --git a/block/blk-merge.c b/block/blk-merge.c
@@ -472,7 +472,7 @@ static int __blk_bios_map_sg(struct request_queue *q, struct bio *bio,
 			     struct scatterlist *sglist,
 			     struct scatterlist **sg)
 {
-	struct bio_vec uninitialized_var(bvec), bvprv = { NULL };
+	struct bio_vec bvec, bvprv = { NULL };
 	struct bvec_iter iter;
 	int nsegs = 0;
 	bool new_bio = false;

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
@@ -93,7 +93,7 @@ static ssize_t ata_scsi_park_show(struct device *device,
 	struct ata_link *link;
 	struct ata_device *dev;
 	unsigned long now;
-	unsigned int uninitialized_var(msecs);
+	unsigned int msecs;
 	int rc = 0;
 
 	ap = ata_shost_to_port(sdev->host);

diff --git a/drivers/atm/zatm.c b/drivers/atm/zatm.c
@@ -940,7 +940,7 @@ static int open_tx_first(struct atm_vcc *vcc)
 	    vcc->qos.txtp.max_pcr >= ATM_OC3_PCR);
 	if (unlimited && zatm_dev->ubr != -1) zatm_vcc->shaper = zatm_dev->ubr;
 	else {
-		int uninitialized_var(pcr);
+		int pcr;
 
 		if (unlimited) vcc->qos.txtp.max_sdu = ATM_MAX_AAL5_PDU;
 		if ((zatm_vcc->shaper = alloc_shaper(vcc->dev,&pcr,

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
@@ -3423,7 +3423,7 @@ int drbd_adm_dump_devices(struct sk_buff *skb, struct netlink_callback *cb)
 {
 	struct nlattr *resource_filter;
 	struct drbd_resource *resource;
-	struct drbd_device *uninitialized_var(device);
+	struct drbd_device *device;
 	int minor, err, retcode;
 	struct drbd_genlmsghdr *dh;
 	struct device_info device_info;
@@ -3512,7 +3512,7 @@ int drbd_adm_dump_connections(struct sk_buff *skb, struct netlink_callback *cb)
 {
 	struct nlattr *resource_filter;
 	struct drbd_resource *resource = NULL, *next_resource;
-	struct drbd_connection *uninitialized_var(connection);
+	struct drbd_connection *connection;
 	int err = 0, retcode;
 	struct drbd_genlmsghdr *dh;
 	struct connection_info connection_info;
@@ -3674,7 +3674,7 @@ int drbd_adm_dump_peer_devices(struct sk_buff *skb, struct netlink_callback *cb)
 {
 	struct nlattr *resource_filter;
 	struct drbd_resource *resource;
-	struct drbd_device *uninitialized_var(device);
+	struct drbd_device *device;
 	struct drbd_peer_device *peer_device = NULL;
 	int minor, err, retcode;
 	struct drbd_genlmsghdr *dh;

diff --git a/drivers/block/drbd/drbd_state.c b/drivers/block/drbd/drbd_state.c
@@ -1604,7 +1604,7 @@ static void broadcast_state_change(struct drbd_state_change *state_change)
 	unsigned int n_device, n_connection, n_peer_device, n_peer_devices;
 	void (*last_func)(struct sk_buff *, unsigned int, void *,
 			  enum drbd_notification_type) = NULL;
-	void *uninitialized_var(last_arg);
+	void *last_arg = NULL;
 
 #define HAS_CHANGED(state) ((state)[OLD] != (state)[NEW])
 #define FINAL_STATE_CHANGE(type) \

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
@@ -1993,7 +1993,7 @@ static int rbd_object_map_update_finish(struct rbd_obj_request *obj_req,
 	struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
 	struct ceph_osd_data *osd_data;
 	u64 objno;
-	u8 state, new_state, uninitialized_var(current_state);
+	u8 state, new_state, current_state;
 	bool has_current_state;
 	void *p;
 

diff --git a/drivers/clk/clk-gate.c b/drivers/clk/clk-gate.c
@@ -56,7 +56,7 @@ static void clk_gate_endisable(struct clk_hw *hw, int enable)
 {
 	struct clk_gate *gate = to_clk_gate(hw);
 	int set = gate->flags & CLK_GATE_SET_TO_DISABLE ? 1 : 0;
-	unsigned long uninitialized_var(flags);
+	unsigned long flags;
 	u32 reg;
 
 	set ^= enable;

diff --git a/drivers/clk/spear/clk-vco-pll.c b/drivers/clk/spear/clk-vco-pll.c
@@ -147,7 +147,7 @@ static int clk_pll_set_rate(struct clk_hw *hw, unsigned long drate,
 	struct clk_pll *pll = to_clk_pll(hw);
 	struct pll_rate_tbl *rtbl = pll->vco->rtbl;
 	unsigned long flags = 0, val;
-	int uninitialized_var(i);
+	int i = 0;
 
 	clk_pll_round_rate_index(hw, drate, NULL, &i);
 

diff --git a/drivers/clk/st/clkgen-fsyn.c b/drivers/clk/st/clkgen-fsyn.c
@@ -790,7 +790,6 @@ static int quadfs_set_rate(struct clk_hw *hw, unsigned long rate,
 	struct st_clk_quadfs_fsynth *fs = to_quadfs_fsynth(hw);
 	struct stm_fs params;
 	long hwrate;
-	int uninitialized_var(i);
 
 	if (!rate || !parent_rate)
 		return -EINVAL;