From b234ed6d629420827e2839c8c8935be85a0867fd Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Tue, 7 Sep 2021 20:00:03 -0700 Subject: init: move usermodehelper_enable() to populate_rootfs() Currently, usermodehelper is enabled right before PID1 starts going through the initcalls. However, any call of a usermodehelper from a pure_, core_, postcore_, arch_, subsys_ or fs_ initcall is futile, as there is no filesystem contents yet. Up until commit e7cb072eb988 ("init/initramfs.c: do unpacking asynchronously"), such calls, whether via some request_module(), a legacy uevent "/sbin/hotplug" notification or something else, would just fail silently with (presumably) -ENOENT from kernel_execve(). However, that commit introduced the wait_for_initramfs() synchronization hook which must be called from the usermodehelper exec path right before the kernel_execve, in order that request_module() et al done from *after* rootfs_initcall() time (i.e. device_ and late_ initcalls) would continue to find a populated initramfs as they used to. Any call of wait_for_initramfs() done before the unpacking has been scheduled (i.e. before rootfs_initcall time) must just return immediately [and let the caller find an empty file system] in order not to deadlock the machine. I mistakenly thought, and my limited testing confirmed, that there were no such calls, so I added a pr_warn_once() in wait_for_initramfs(). It turns out that one can indeed hit request_module() as well as kobject_uevent_env() during those early init calls, leading to a user-visible warning in the kernel log emitted consistently for certain configurations. We could just remove the pr_warn_once(), but I think it's better to postpone enabling the usermodehelper framework until there is at least some chance of finding the executable. That is also a little more efficient in that a lot of work done in umh.c will be elided. However, it does change the error seen by those early callers from -ENOENT to -EBUSY, so there is a risk of a regression if any caller care about the exact error value. Link: https://lkml.kernel.org/r/20210728134638.329060-1-linux@rasmusvillemoes.dk Fixes: e7cb072eb988 ("init/initramfs.c: do unpacking asynchronously") Signed-off-by: Rasmus Villemoes Reported-by: Alexander Egorenkov Reported-by: Bruno Goncalves Reported-by: Heiner Kallweit Cc: Luis Chamberlain Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- init/initramfs.c | 2 ++ init/main.c | 1 - init/noinitramfs.c | 2 ++ 3 files changed, 4 insertions(+), 1 deletion(-) (limited to 'init') diff --git a/init/initramfs.c b/init/initramfs.c index af27abc59643..a842c0544745 100644 --- a/init/initramfs.c +++ b/init/initramfs.c @@ -15,6 +15,7 @@ #include #include #include +#include static ssize_t __init xwrite(struct file *file, const char *p, size_t count, loff_t *pos) @@ -727,6 +728,7 @@ static int __init populate_rootfs(void) { initramfs_cookie = async_schedule_domain(do_populate_rootfs, NULL, &initramfs_domain); + usermodehelper_enable(); if (!initramfs_async) wait_for_initramfs(); return 0; diff --git a/init/main.c b/init/main.c index 8d97aba78c3a..90733a916791 100644 --- a/init/main.c +++ b/init/main.c @@ -1392,7 +1392,6 @@ static void __init do_basic_setup(void) driver_init(); init_irq_proc(); do_ctors(); - usermodehelper_enable(); do_initcalls(); } diff --git a/init/noinitramfs.c b/init/noinitramfs.c index 3d62b07f3bb9..d1d26b93d25c 100644 --- a/init/noinitramfs.c +++ b/init/noinitramfs.c @@ -10,6 +10,7 @@ #include #include #include +#include /* * Create a simple rootfs that is similar to the default initramfs @@ -18,6 +19,7 @@ static int __init default_rootfs(void) { int err; + usermodehelper_enable(); err = init_mkdir("/dev", 0755); if (err < 0) goto out; -- cgit v1.2.3 From 8b097881b54cbc23dd78262ed88c9924d00ea457 Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Tue, 7 Sep 2021 20:16:06 -0700 Subject: trap: cleanup trap_init() There are some empty trap_init() definitions in different ARCHs, Introduce a new weak trap_init() function to clean them up. Link: https://lkml.kernel.org/r/20210812123602.76356-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Acked-by: Russell King (Oracle) [arm32] Acked-by: Vineet Gupta [arc] Acked-by: Michael Ellerman [powerpc] Cc: Yoshinori Sato Cc: Ley Foon Tan Cc: Jonas Bonn Cc: Stefan Kristiansson Cc: Stafford Horne Cc: James E.J. Bottomley Cc: Helge Deller Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Paul Walmsley Cc: Jeff Dike Cc: Richard Weinberger Cc: Anton Ivanov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/arc/kernel/traps.c | 5 ----- arch/arm/kernel/traps.c | 5 ----- arch/h8300/kernel/traps.c | 4 ---- arch/hexagon/kernel/traps.c | 4 ---- arch/nds32/kernel/traps.c | 5 ----- arch/nios2/kernel/traps.c | 5 ----- arch/openrisc/kernel/traps.c | 5 ----- arch/parisc/kernel/traps.c | 4 ---- arch/powerpc/kernel/traps.c | 5 ----- arch/riscv/kernel/traps.c | 5 ----- arch/um/kernel/trap.c | 4 ---- init/main.c | 2 ++ 12 files changed, 2 insertions(+), 51 deletions(-) (limited to 'init') diff --git a/arch/arc/kernel/traps.c b/arch/arc/kernel/traps.c index 57235e5c0cea..6b83e3f2b41c 100644 --- a/arch/arc/kernel/traps.c +++ b/arch/arc/kernel/traps.c @@ -20,11 +20,6 @@ #include #include -void __init trap_init(void) -{ - return; -} - void die(const char *str, struct pt_regs *regs, unsigned long address) { show_kernel_fault_diag(str, regs, address); diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index 64308e3a5d0c..e9b4f2b49bd8 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -781,11 +781,6 @@ void abort(void) panic("Oops failed to kill thread"); } -void __init trap_init(void) -{ - return; -} - #ifdef CONFIG_KUSER_HELPERS static void __init kuser_init(void *vectors) { diff --git a/arch/h8300/kernel/traps.c b/arch/h8300/kernel/traps.c index 5d8b969cd8f3..bdbe988d8dbc 100644 --- a/arch/h8300/kernel/traps.c +++ b/arch/h8300/kernel/traps.c @@ -39,10 +39,6 @@ void __init base_trap_init(void) { } -void __init trap_init(void) -{ -} - asmlinkage void set_esp0(unsigned long ssp) { current->thread.esp0 = ssp; diff --git a/arch/hexagon/kernel/traps.c b/arch/hexagon/kernel/traps.c index 904134b37232..edfc35dafeb1 100644 --- a/arch/hexagon/kernel/traps.c +++ b/arch/hexagon/kernel/traps.c @@ -28,10 +28,6 @@ #define TRAP_SYSCALL 1 #define TRAP_DEBUG 0xdb -void __init trap_init(void) -{ -} - #ifdef CONFIG_GENERIC_BUG /* Maybe should resemble arch/sh/kernel/traps.c ?? */ int is_valid_bugaddr(unsigned long addr) diff --git a/arch/nds32/kernel/traps.c b/arch/nds32/kernel/traps.c index ee0d9ae192a5..f06421c645af 100644 --- a/arch/nds32/kernel/traps.c +++ b/arch/nds32/kernel/traps.c @@ -183,11 +183,6 @@ void __pgd_error(const char *file, int line, unsigned long val) } extern char *exception_vector, *exception_vector_end; -void __init trap_init(void) -{ - return; -} - void __init early_trap_init(void) { unsigned long ivb = 0; diff --git a/arch/nios2/kernel/traps.c b/arch/nios2/kernel/traps.c index b172da4eb1a9..596986a74a26 100644 --- a/arch/nios2/kernel/traps.c +++ b/arch/nios2/kernel/traps.c @@ -105,11 +105,6 @@ void show_stack(struct task_struct *task, unsigned long *stack, printk("%s\n", loglvl); } -void __init trap_init(void) -{ - /* Nothing to do here */ -} - /* Breakpoint handler */ asmlinkage void breakpoint_c(struct pt_regs *fp) { diff --git a/arch/openrisc/kernel/traps.c b/arch/openrisc/kernel/traps.c index 4d61333c2623..aa1e709405ac 100644 --- a/arch/openrisc/kernel/traps.c +++ b/arch/openrisc/kernel/traps.c @@ -231,11 +231,6 @@ void unhandled_exception(struct pt_regs *regs, int ea, int vector) die("Oops", regs, 9); } -void __init trap_init(void) -{ - /* Nothing needs to be done */ -} - asmlinkage void do_trap(struct pt_regs *regs, unsigned long address) { force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->pc); diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c index 8d8441d4562a..747c328fb886 100644 --- a/arch/parisc/kernel/traps.c +++ b/arch/parisc/kernel/traps.c @@ -859,7 +859,3 @@ void __init early_trap_init(void) initialize_ivt(&fault_vector_20); } - -void __init trap_init(void) -{ -} diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index d56254f05e17..7819231242b2 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -2215,11 +2215,6 @@ DEFINE_INTERRUPT_HANDLER(kernel_bad_stack) die("Bad kernel stack pointer", regs, SIGABRT); } -void __init trap_init(void) -{ -} - - #ifdef CONFIG_PPC_EMULATED_STATS #define WARN_EMULATED_SETUP(type) .type = { .name = #type } diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c index 0a98fd0ddfe9..0daaa3e4630d 100644 --- a/arch/riscv/kernel/traps.c +++ b/arch/riscv/kernel/traps.c @@ -199,11 +199,6 @@ int is_valid_bugaddr(unsigned long pc) } #endif /* CONFIG_GENERIC_BUG */ -/* stvec & scratch is already set from head.S */ -void __init trap_init(void) -{ -} - #ifdef CONFIG_VMAP_STACK static DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack)__aligned(16); diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c index ad12f78bda7e..3198c4767387 100644 --- a/arch/um/kernel/trap.c +++ b/arch/um/kernel/trap.c @@ -311,7 +311,3 @@ void winch(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs) { do_IRQ(WINCH_IRQ, regs); } - -void trap_init(void) -{ -} diff --git a/init/main.c b/init/main.c index 90733a916791..4a52392abd02 100644 --- a/init/main.c +++ b/init/main.c @@ -777,6 +777,8 @@ void __init __weak poking_init(void) { } void __init __weak pgtable_cache_init(void) { } +void __init __weak trap_init(void) { } + bool initcall_debug; core_param(initcall_debug, initcall_debug, bool, 0644); -- cgit v1.2.3