From a88108e90ca0c1d5f1631df4951459b6def12f75 Mon Sep 17 00:00:00 2001 From: Douglas Anderson Date: Tue, 30 Oct 2018 15:11:04 -0700 Subject: serial: core: Allow processing sysrq at port unlock time [ Upstream commit d6e1935819db0c91ce4a5af82466f3ab50d17346 ] Right now serial drivers process sysrq keys deep in their character receiving code. This means that they've already grabbed their port->lock spinlock. This can end up getting in the way if we've go to do serial stuff (especially kgdb) in response to the sysrq. Serial drivers have various hacks in them to handle this. Looking at '8250_port.c' you can see that the console_write() skips locking if we're in the sysrq handler. Looking at 'msm_serial.c' you can see that the port lock is dropped around uart_handle_sysrq_char(). It turns out that these hacks aren't exactly perfect. If you have lockdep turned on and use something like the 8250_port hack you'll get a splat that looks like: WARNING: possible circular locking dependency detected [...] is trying to acquire lock: ... (console_owner){-.-.}, at: console_unlock+0x2e0/0x5e4 but task is already holding lock: ... (&port_lock_key){-.-.}, at: serial8250_handle_irq+0x30/0xe4 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&port_lock_key){-.-.}: _raw_spin_lock_irqsave+0x58/0x70 serial8250_console_write+0xa8/0x250 univ8250_console_write+0x40/0x4c console_unlock+0x528/0x5e4 register_console+0x2c4/0x3b0 uart_add_one_port+0x350/0x478 serial8250_register_8250_port+0x350/0x3a8 dw8250_probe+0x67c/0x754 platform_drv_probe+0x58/0xa4 really_probe+0x150/0x294 driver_probe_device+0xac/0xe8 __driver_attach+0x98/0xd0 bus_for_each_dev+0x84/0xc8 driver_attach+0x2c/0x34 bus_add_driver+0xf0/0x1ec driver_register+0xb4/0x100 __platform_driver_register+0x60/0x6c dw8250_platform_driver_init+0x20/0x28 ... -> #0 (console_owner){-.-.}: lock_acquire+0x1e8/0x214 console_unlock+0x35c/0x5e4 vprintk_emit+0x230/0x274 vprintk_default+0x7c/0x84 vprintk_func+0x190/0x1bc printk+0x80/0xa0 __handle_sysrq+0x104/0x21c handle_sysrq+0x30/0x3c serial8250_read_char+0x15c/0x18c serial8250_rx_chars+0x34/0x74 serial8250_handle_irq+0x9c/0xe4 dw8250_handle_irq+0x98/0xcc serial8250_interrupt+0x50/0xe8 ... other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&port_lock_key); lock(console_owner); lock(&port_lock_key); lock(console_owner); *** DEADLOCK *** The hack used in 'msm_serial.c' doesn't cause the above splats but it seems a bit ugly to unlock / lock our spinlock deep in our irq handler. It seems like we could defer processing the sysrq until the end of the interrupt handler right after we've unlocked the port. With this scheme if a whole batch of sysrq characters comes in one irq then we won't handle them all, but that seems like it should be a fine compromise. Signed-off-by: Douglas Anderson Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- include/linux/serial_core.h | 37 ++++++++++++++++++++++++++++++++++++- 1 file changed, 36 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 297d4fa1cfe5..b5b527efeea0 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -159,6 +159,7 @@ struct uart_port { struct console *cons; /* struct console, if any */ #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(SUPPORT_SYSRQ) unsigned long sysrq; /* sysrq timeout */ + unsigned int sysrq_ch; /* char for sysrq */ #endif /* flags must be updated while holding port mutex */ @@ -440,8 +441,42 @@ uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) } return 0; } +static inline int +uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) +{ + if (port->sysrq) { + if (ch && time_before(jiffies, port->sysrq)) { + port->sysrq_ch = ch; + port->sysrq = 0; + return 1; + } + port->sysrq = 0; + } + return 0; +} +static inline void +uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags) +{ + int sysrq_ch; + + sysrq_ch = port->sysrq_ch; + port->sysrq_ch = 0; + + spin_unlock_irqrestore(&port->lock, irqflags); + + if (sysrq_ch) + handle_sysrq(sysrq_ch); +} #else -#define uart_handle_sysrq_char(port,ch) ({ (void)port; 0; }) +static inline int +uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) { return 0; } +static inline int +uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) { return 0; } +static inline void +uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags) +{ + spin_unlock_irqrestore(&port->lock, irqflags); +} #endif /* -- cgit v1.2.3 From ad2cfd2e1a54b3971a5192e74d1abc11b54e2f5b Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Fri, 16 Nov 2018 19:19:30 -0800 Subject: regulator: Fix return value of _set_load() stub [ Upstream commit f1abf67217de91f5cd3c757ae857632ca565099a ] The stub implementation of _set_load() returns a mode value which is within the bounds of valid return codes for success (the documentation just says that failures are negative error codes) but not sensible or what the actual implementation does. Fix it to just return 0. Reported-by: Cheng-Yi Chiang Signed-off-by: Mark Brown Reviewed-by: Douglas Anderson Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- include/linux/regulator/consumer.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/regulator/consumer.h b/include/linux/regulator/consumer.h index 9e0e76992be0..bf62713af290 100644 --- a/include/linux/regulator/consumer.h +++ b/include/linux/regulator/consumer.h @@ -485,7 +485,7 @@ static inline unsigned int regulator_get_mode(struct regulator *regulator) static inline int regulator_set_load(struct regulator *regulator, int load_uA) { - return REGULATOR_MODE_NORMAL; + return 0; } static inline int regulator_allow_bypass(struct regulator *regulator, -- cgit v1.2.3 From 54ad7dd6bc8a80643160cedee44a6ea04917e502 Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Fri, 23 Nov 2018 23:07:14 +0300 Subject: ACPI: fix acpi_find_child_device() invocation in acpi_preset_companion() [ Upstream commit f8c6d1402b89f22a3647705d63cbd171aa19a77e ] acpi_find_child_device() accepts boolean not pointer as last argument. Signed-off-by: Alexey Dobriyan [ rjw: Subject ] Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- include/linux/acpi.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 6a30f1e03aa9..0bd0a9ad5455 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -75,7 +75,7 @@ static inline bool has_acpi_companion(struct device *dev) static inline void acpi_preset_companion(struct device *dev, struct acpi_device *parent, u64 addr) { - ACPI_COMPANION_SET(dev, acpi_find_child_device(parent, addr, NULL)); + ACPI_COMPANION_SET(dev, acpi_find_child_device(parent, addr, false)); } static inline const char *acpi_dev_name(struct acpi_device *adev) -- cgit v1.2.3 From f636b81fbaab49877126dcda613af6600f892b67 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Niklas=20S=C3=B6derlund?= Date: Wed, 29 Aug 2018 23:29:21 +0200 Subject: dma-mapping: fix return type of dma_set_max_seg_size() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [ Upstream commit c9d76d0655c06b8c1f944e46c4fd9e9cf4b331c0 ] The function dma_set_max_seg_size() can return either 0 on success or -EIO on error. Change its return type from unsigned int to int to capture this. Signed-off-by: Niklas Söderlund Reviewed-by: Geert Uytterhoeven Signed-off-by: Christoph Hellwig Signed-off-by: Sasha Levin --- include/linux/dma-mapping.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index 2e551e2d2d03..62dd6676b7cc 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -151,8 +151,7 @@ static inline unsigned int dma_get_max_seg_size(struct device *dev) return SZ_64K; } -static inline unsigned int dma_set_max_seg_size(struct device *dev, - unsigned int size) +static inline int dma_set_max_seg_size(struct device *dev, unsigned int size) { if (dev->dma_parms) { dev->dma_parms->max_segment_size = size; -- cgit v1.2.3 From 799a03be21afbd82d3633228ff2b889e223405a6 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 5 Nov 2019 17:44:07 +0100 Subject: jbd2: Fix possible overflow in jbd2_log_space_left() commit add3efdd78b8a0478ce423bb9d4df6bd95e8b335 upstream. When number of free space in the journal is very low, the arithmetic in jbd2_log_space_left() could underflow resulting in very high number of free blocks and thus triggering assertion failure in transaction commit code complaining there's not enough space in the journal: J_ASSERT(journal->j_free > 1); Properly check for the low number of free blocks. CC: stable@vger.kernel.org Reviewed-by: Theodore Ts'o Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20191105164437.32602-1-jack@suse.cz Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- include/linux/jbd2.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h index 65407f6c9120..00108208759d 100644 --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -1440,7 +1440,7 @@ static inline int jbd2_space_needed(journal_t *journal) static inline unsigned long jbd2_log_space_left(journal_t *journal) { /* Allow for rounding errors */ - unsigned long free = journal->j_free - 32; + long free = journal->j_free - 32; if (journal->j_committing_transaction) { unsigned long committing = atomic_read(&journal-> @@ -1449,7 +1449,7 @@ static inline unsigned long jbd2_log_space_left(journal_t *journal) /* Transaction + control blocks */ free -= committing + (committing >> JBD2_CONTROL_BLOCKS_SHIFT); } - return free; + return max_t(long, free, 0); } /* -- cgit v1.2.3 From 7ae3525ee708f867a2d2321c246b285136cdbed8 Mon Sep 17 00:00:00 2001 From: YueHaibing Date: Thu, 14 Mar 2019 13:47:59 +0800 Subject: appletalk: Fix potential NULL pointer dereference in unregister_snap_client commit 9804501fa1228048857910a6bf23e085aade37cc upstream. register_snap_client may return NULL, all the callers check it, but only print a warning. This will result in NULL pointer dereference in unregister_snap_client and other places. It has always been used like this since v2.6 Reported-by: Dan Carpenter Signed-off-by: YueHaibing Signed-off-by: David S. Miller [bwh: Backported to <4.15: adjust context] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- include/linux/atalk.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/atalk.h b/include/linux/atalk.h index af43ed404ff4..4be0e14b38fc 100644 --- a/include/linux/atalk.h +++ b/include/linux/atalk.h @@ -107,7 +107,7 @@ static __inline__ struct elapaarp *aarp_hdr(struct sk_buff *skb) #define AARP_RESOLVE_TIME (10 * HZ) extern struct datalink_proto *ddp_dl, *aarp_dl; -extern void aarp_proto_init(void); +extern int aarp_proto_init(void); /* Inter module exports */ -- cgit v1.2.3 From 1354c2fa639636e3b83a736fb29eb449477c64f9 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Tue, 13 Sep 2016 14:29:24 -0700 Subject: sched/core: Allow putting thread_info into task_struct commit c65eacbe290b8141554c71b2c94489e73ade8c8d upstream. If an arch opts in by setting CONFIG_THREAD_INFO_IN_TASK_STRUCT, then thread_info is defined as a single 'u32 flags' and is the first entry of task_struct. thread_info::task is removed (it serves no purpose if thread_info is embedded in task_struct), and thread_info::cpu gets its own slot in task_struct. This is heavily based on a patch written by Linus. Originally-from: Linus Torvalds Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Jann Horn Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/a0898196f0476195ca02713691a5037a14f2aac5.1473801993.git.luto@kernel.org Signed-off-by: Ingo Molnar Signed-off-by: zhangyi (F) Signed-off-by: Greg Kroah-Hartman --- include/linux/init_task.h | 9 +++++++++ include/linux/sched.h | 36 ++++++++++++++++++++++++++++++++++-- include/linux/thread_info.h | 15 +++++++++++++++ 3 files changed, 58 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/init_task.h b/include/linux/init_task.h index 1c1ff7e4faa4..d25d3f70ee99 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -15,6 +15,8 @@ #include #include +#include + #ifdef CONFIG_SMP # define INIT_PUSHABLE_TASKS(tsk) \ .pushable_tasks = PLIST_NODE_INIT(tsk.pushable_tasks, MAX_PRIO), @@ -183,12 +185,19 @@ extern struct task_group root_task_group; # define INIT_KASAN(tsk) #endif +#ifdef CONFIG_THREAD_INFO_IN_TASK +# define INIT_TASK_TI(tsk) .thread_info = INIT_THREAD_INFO(tsk), +#else +# define INIT_TASK_TI(tsk) +#endif + /* * INIT_TASK is used to set up the first task table, touch at * your own risk!. Base=0, limit=0x1fffff (=2MB) */ #define INIT_TASK(tsk) \ { \ + INIT_TASK_TI(tsk) \ .state = 0, \ .stack = &init_thread_info, \ .usage = ATOMIC_INIT(2), \ diff --git a/include/linux/sched.h b/include/linux/sched.h index 1218980f53de..d6b2e77aad3f 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1389,6 +1389,13 @@ struct tlbflush_unmap_batch { }; struct task_struct { +#ifdef CONFIG_THREAD_INFO_IN_TASK + /* + * For reasons of header soup (see current_thread_info()), this + * must be the first element of task_struct. + */ + struct thread_info thread_info; +#endif volatile long state; /* -1 unrunnable, 0 runnable, >0 stopped */ void *stack; atomic_t usage; @@ -1398,6 +1405,9 @@ struct task_struct { #ifdef CONFIG_SMP struct llist_node wake_entry; int on_cpu; +#ifdef CONFIG_THREAD_INFO_IN_TASK + unsigned int cpu; /* current CPU */ +#endif unsigned int wakee_flips; unsigned long wakee_flip_decay_ts; struct task_struct *last_wakee; @@ -2440,7 +2450,9 @@ extern void set_curr_task(int cpu, struct task_struct *p); void yield(void); union thread_union { +#ifndef CONFIG_THREAD_INFO_IN_TASK struct thread_info thread_info; +#endif unsigned long stack[THREAD_SIZE/sizeof(long)]; }; @@ -2840,10 +2852,26 @@ static inline void threadgroup_change_end(struct task_struct *tsk) cgroup_threadgroup_change_end(tsk); } -#ifndef __HAVE_THREAD_FUNCTIONS +#ifdef CONFIG_THREAD_INFO_IN_TASK + +static inline struct thread_info *task_thread_info(struct task_struct *task) +{ + return &task->thread_info; +} +static inline void *task_stack_page(const struct task_struct *task) +{ + return task->stack; +} +#define setup_thread_stack(new,old) do { } while(0) +static inline unsigned long *end_of_stack(const struct task_struct *task) +{ + return task->stack; +} + +#elif !defined(__HAVE_THREAD_FUNCTIONS) #define task_thread_info(task) ((struct thread_info *)(task)->stack) -#define task_stack_page(task) ((task)->stack) +#define task_stack_page(task) ((void *)(task)->stack) static inline void setup_thread_stack(struct task_struct *p, struct task_struct *org) { @@ -3135,7 +3163,11 @@ static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume) static inline unsigned int task_cpu(const struct task_struct *p) { +#ifdef CONFIG_THREAD_INFO_IN_TASK + return p->cpu; +#else return task_thread_info(p)->cpu; +#endif } static inline int task_node(const struct task_struct *p) diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h index 646891f3bc1e..2813de75a96e 100644 --- a/include/linux/thread_info.h +++ b/include/linux/thread_info.h @@ -13,6 +13,21 @@ struct timespec; struct compat_timespec; +#ifdef CONFIG_THREAD_INFO_IN_TASK +struct thread_info { + u32 flags; /* low level flags */ +}; + +#define INIT_THREAD_INFO(tsk) \ +{ \ + .flags = 0, \ +} +#endif + +#ifdef CONFIG_THREAD_INFO_IN_TASK +#define current_thread_info() ((struct thread_info *)current) +#endif + /* * System call restart block. */ -- cgit v1.2.3 From 002cc9ee358bfeb21490830b6ba34ba217ef22eb Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Thu, 15 Sep 2016 22:45:43 -0700 Subject: sched/core: Add try_get_task_stack() and put_task_stack() commit c6c314a613cd7d03fb97713e0d642b493de42e69 upstream. There are a few places in the kernel that access stack memory belonging to a different task. Before we can start freeing task stacks before the task_struct is freed, we need a way for those code paths to pin the stack. Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Jann Horn Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/17a434f50ad3d77000104f21666575e10a9c1fbd.1474003868.git.luto@kernel.org Signed-off-by: Ingo Molnar Signed-off-by: zhangyi (F) Signed-off-by: Greg Kroah-Hartman --- include/linux/sched.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'include/linux') diff --git a/include/linux/sched.h b/include/linux/sched.h index d6b2e77aad3f..761247c966a5 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2858,11 +2858,19 @@ static inline struct thread_info *task_thread_info(struct task_struct *task) { return &task->thread_info; } + +/* + * When accessing the stack of a non-current task that might exit, use + * try_get_task_stack() instead. task_stack_page will return a pointer + * that could get freed out from under you. + */ static inline void *task_stack_page(const struct task_struct *task) { return task->stack; } + #define setup_thread_stack(new,old) do { } while(0) + static inline unsigned long *end_of_stack(const struct task_struct *task) { return task->stack; @@ -2898,6 +2906,14 @@ static inline unsigned long *end_of_stack(struct task_struct *p) } #endif + +static inline void *try_get_task_stack(struct task_struct *tsk) +{ + return task_stack_page(tsk); +} + +static inline void put_task_stack(struct task_struct *tsk) {} + #define task_stack_end_corrupted(task) \ (*(end_of_stack(task)) != STACK_END_MAGIC) -- cgit v1.2.3 From 0d47fd93cdc01c7b78c0970601461b571dddc58f Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Wed, 19 Oct 2016 19:28:11 +0100 Subject: sched/core, x86: Make struct thread_info arch specific again commit c8061485a0d7569a865a3cc3c63347b0f42b3765 upstream. The following commit: c65eacbe290b ("sched/core: Allow putting thread_info into task_struct") ... made 'struct thread_info' a generic struct with only a single ::flags member, if CONFIG_THREAD_INFO_IN_TASK_STRUCT=y is selected. This change however seems to be quite x86 centric, since at least the generic preemption code (asm-generic/preempt.h) assumes that struct thread_info also has a preempt_count member, which apparently was not true for x86. We could add a bit more #ifdefs to solve this problem too, but it seems to be much simpler to make struct thread_info arch specific again. This also makes the conversion to THREAD_INFO_IN_TASK_STRUCT a bit easier for architectures that have a couple of arch specific stuff in their thread_info definition. The arch specific stuff _could_ be moved to thread_struct. However keeping them in thread_info makes it easier: accessing thread_info members is simple, since it is at the beginning of the task_struct, while the thread_struct is at the end. At least on s390 the offsets needed to access members of the thread_struct (with task_struct as base) are too large for various asm instructions. This is not a problem when keeping these members within thread_info. Signed-off-by: Heiko Carstens Signed-off-by: Mark Rutland Acked-by: Thomas Gleixner Cc: Andrew Morton Cc: Andy Lutomirski Cc: Linus Torvalds Cc: Peter Zijlstra Cc: keescook@chromium.org Cc: linux-arch@vger.kernel.org Link: http://lkml.kernel.org/r/1476901693-8492-2-git-send-email-mark.rutland@arm.com Signed-off-by: Ingo Molnar [ zhangyi: skip defination of INIT_THREAD_INFO and struct thread_info ] Signed-off-by: zhangyi (F) Signed-off-by: Greg Kroah-Hartman --- include/linux/thread_info.h | 11 ----------- 1 file changed, 11 deletions(-) (limited to 'include/linux') diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h index 2813de75a96e..897e835379d8 100644 --- a/include/linux/thread_info.h +++ b/include/linux/thread_info.h @@ -13,17 +13,6 @@ struct timespec; struct compat_timespec; -#ifdef CONFIG_THREAD_INFO_IN_TASK -struct thread_info { - u32 flags; /* low level flags */ -}; - -#define INIT_THREAD_INFO(tsk) \ -{ \ - .flags = 0, \ -} -#endif - #ifdef CONFIG_THREAD_INFO_IN_TASK #define current_thread_info() ((struct thread_info *)current) #endif -- cgit v1.2.3 From d465999c71d22a670b21762e683b1e64bd873e44 Mon Sep 17 00:00:00 2001 From: Dmitry Monakhov Date: Thu, 31 Oct 2019 10:39:20 +0000 Subject: quota: Check that quota is not dirty before release commit df4bb5d128e2c44848aeb36b7ceceba3ac85080d upstream. There is a race window where quota was redirted once we drop dq_list_lock inside dqput(), but before we grab dquot->dq_lock inside dquot_release() TASK1 TASK2 (chowner) ->dqput() we_slept: spin_lock(&dq_list_lock) if (dquot_dirty(dquot)) { spin_unlock(&dq_list_lock); dquot->dq_sb->dq_op->write_dquot(dquot); goto we_slept if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) { spin_unlock(&dq_list_lock); dquot->dq_sb->dq_op->release_dquot(dquot); dqget() mark_dquot_dirty() dqput() goto we_slept; } So dquot dirty quota will be released by TASK1, but on next we_sleept loop we detect this and call ->write_dquot() for it. XFSTEST: https://github.com/dmonakhov/xfstests/commit/440a80d4cbb39e9234df4d7240aee1d551c36107 Link: https://lore.kernel.org/r/20191031103920.3919-2-dmonakhov@openvz.org CC: stable@vger.kernel.org Signed-off-by: Dmitry Monakhov Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman --- include/linux/quotaops.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'include/linux') diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h index 1f350238445c..a946c4c1a77e 100644 --- a/include/linux/quotaops.h +++ b/include/linux/quotaops.h @@ -54,6 +54,16 @@ static inline struct dquot *dqgrab(struct dquot *dquot) atomic_inc(&dquot->dq_count); return dquot; } + +static inline bool dquot_is_busy(struct dquot *dquot) +{ + if (test_bit(DQ_MOD_B, &dquot->dq_flags)) + return true; + if (atomic_read(&dquot->dq_count) > 1) + return true; + return false; +} + void dqput(struct dquot *dquot); int dquot_scan_active(struct super_block *sb, int (*fn)(struct dquot *dquot, unsigned long priv), -- cgit v1.2.3 From 9052980abf9a61a059a3bb105172bc24a3a98f15 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 5 Dec 2019 20:43:46 -0800 Subject: inet: protect against too small mtu values. [ Upstream commit 501a90c945103e8627406763dac418f20f3837b2 ] syzbot was once again able to crash a host by setting a very small mtu on loopback device. Let's make inetdev_valid_mtu() available in include/net/ip.h, and use it in ip_setup_cork(), so that we protect both ip_append_page() and __ip_append_data() Also add a READ_ONCE() when the device mtu is read. Pairs this lockless read with one WRITE_ONCE() in __dev_set_mtu(), even if other code paths might write over this field. Add a big comment in include/linux/netdevice.h about dev->mtu needing READ_ONCE()/WRITE_ONCE() annotations. Hopefully we will add the missing ones in followup patches. [1] refcount_t: saturated; leaking memory. WARNING: CPU: 0 PID: 9464 at lib/refcount.c:22 refcount_warn_saturate+0x138/0x1f0 lib/refcount.c:22 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 9464 Comm: syz-executor850 Not tainted 5.4.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 panic+0x2e3/0x75c kernel/panic.c:221 __warn.cold+0x2f/0x3e kernel/panic.c:582 report_bug+0x289/0x300 lib/bug.c:195 fixup_bug arch/x86/kernel/traps.c:174 [inline] fixup_bug arch/x86/kernel/traps.c:169 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027 RIP: 0010:refcount_warn_saturate+0x138/0x1f0 lib/refcount.c:22 Code: 06 31 ff 89 de e8 c8 f5 e6 fd 84 db 0f 85 6f ff ff ff e8 7b f4 e6 fd 48 c7 c7 e0 71 4f 88 c6 05 56 a6 a4 06 01 e8 c7 a8 b7 fd <0f> 0b e9 50 ff ff ff e8 5c f4 e6 fd 0f b6 1d 3d a6 a4 06 31 ff 89 RSP: 0018:ffff88809689f550 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff815e4336 RDI: ffffed1012d13e9c RBP: ffff88809689f560 R08: ffff88809c50a3c0 R09: fffffbfff15d31b1 R10: fffffbfff15d31b0 R11: ffffffff8ae98d87 R12: 0000000000000001 R13: 0000000000040100 R14: ffff888099041104 R15: ffff888218d96e40 refcount_add include/linux/refcount.h:193 [inline] skb_set_owner_w+0x2b6/0x410 net/core/sock.c:1999 sock_wmalloc+0xf1/0x120 net/core/sock.c:2096 ip_append_page+0x7ef/0x1190 net/ipv4/ip_output.c:1383 udp_sendpage+0x1c7/0x480 net/ipv4/udp.c:1276 inet_sendpage+0xdb/0x150 net/ipv4/af_inet.c:821 kernel_sendpage+0x92/0xf0 net/socket.c:3794 sock_sendpage+0x8b/0xc0 net/socket.c:936 pipe_to_sendpage+0x2da/0x3c0 fs/splice.c:458 splice_from_pipe_feed fs/splice.c:512 [inline] __splice_from_pipe+0x3ee/0x7c0 fs/splice.c:636 splice_from_pipe+0x108/0x170 fs/splice.c:671 generic_splice_sendpage+0x3c/0x50 fs/splice.c:842 do_splice_from fs/splice.c:861 [inline] direct_splice_actor+0x123/0x190 fs/splice.c:1035 splice_direct_to_actor+0x3b4/0xa30 fs/splice.c:990 do_splice_direct+0x1da/0x2a0 fs/splice.c:1078 do_sendfile+0x597/0xd00 fs/read_write.c:1464 __do_sys_sendfile64 fs/read_write.c:1525 [inline] __se_sys_sendfile64 fs/read_write.c:1511 [inline] __x64_sys_sendfile64+0x1dd/0x220 fs/read_write.c:1511 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x441409 Code: e8 ac e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fffb64c4f78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441409 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000005 RBP: 0000000000073b8a R08: 0000000000000010 R09: 0000000000000010 R10: 0000000000010001 R11: 0000000000000246 R12: 0000000000402180 R13: 0000000000402210 R14: 0000000000000000 R15: 0000000000000000 Kernel Offset: disabled Rebooting in 86400 seconds.. Fixes: 1470ddf7f8ce ("inet: Remove explicit write references to sk/inet in ip_append_data") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- include/linux/netdevice.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux') diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 861b71377e5e..d999e503ba8a 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1617,6 +1617,11 @@ struct net_device { unsigned char if_port; unsigned char dma; + /* Note : dev->mtu is often read without holding a lock. + * Writers usually hold RTNL. + * It is recommended to use READ_ONCE() to annotate the reads, + * and to use WRITE_ONCE() to annotate the writes. + */ unsigned int mtu; unsigned short type; unsigned short hard_header_len; -- cgit v1.2.3 From aaa854691f929bf9f738f50c804820fd6518c6ff Mon Sep 17 00:00:00 2001 From: Guillaume Nault Date: Fri, 6 Dec 2019 12:38:36 +0100 Subject: tcp: fix rejected syncookies due to stale timestamps [ Upstream commit 04d26e7b159a396372646a480f4caa166d1b6720 ] If no synflood happens for a long enough period of time, then the synflood timestamp isn't refreshed and jiffies can advance so much that time_after32() can't accurately compare them any more. Therefore, we can end up in a situation where time_after32(now, last_overflow + HZ) returns false, just because these two values are too far apart. In that case, the synflood timestamp isn't updated as it should be, which can trick tcp_synq_no_recent_overflow() into rejecting valid syncookies. For example, let's consider the following scenario on a system with HZ=1000: * The synflood timestamp is 0, either because that's the timestamp of the last synflood or, more commonly, because we're working with a freshly created socket. * We receive a new SYN, which triggers synflood protection. Let's say that this happens when jiffies == 2147484649 (that is, 'synflood timestamp' + HZ + 2^31 + 1). * Then tcp_synq_overflow() doesn't update the synflood timestamp, because time_after32(2147484649, 1000) returns false. With: - 2147484649: the value of jiffies, aka. 'now'. - 1000: the value of 'last_overflow' + HZ. * A bit later, we receive the ACK completing the 3WHS. But cookie_v[46]_check() rejects it because tcp_synq_no_recent_overflow() says that we're not under synflood. That's because time_after32(2147484649, 120000) returns false. With: - 2147484649: the value of jiffies, aka. 'now'. - 120000: the value of 'last_overflow' + TCP_SYNCOOKIE_VALID. Of course, in reality jiffies would have increased a bit, but this condition will last for the next 119 seconds, which is far enough to accommodate for jiffie's growth. Fix this by updating the overflow timestamp whenever jiffies isn't within the [last_overflow, last_overflow + HZ] range. That shouldn't have any performance impact since the update still happens at most once per second. Now we're guaranteed to have fresh timestamps while under synflood, so tcp_synq_no_recent_overflow() can safely use it with time_after32() in such situations. Stale timestamps can still make tcp_synq_no_recent_overflow() return the wrong verdict when not under synflood. This will be handled in the next patch. For 64 bits architectures, the problem was introduced with the conversion of ->tw_ts_recent_stamp to 32 bits integer by commit cca9bab1b72c ("tcp: use monotonic timestamps for PAWS"). The problem has always been there on 32 bits architectures. Fixes: cca9bab1b72c ("tcp: use monotonic timestamps for PAWS") Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Guillaume Nault Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- include/linux/time.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'include/linux') diff --git a/include/linux/time.h b/include/linux/time.h index 297f09f23896..62cc50700004 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -262,4 +262,16 @@ static __always_inline void timespec_add_ns(struct timespec *a, u64 ns) a->tv_nsec = ns; } +/** + * time_between32 - check if a 32-bit timestamp is within a given time range + * @t: the time which may be within [l,h] + * @l: the lower bound of the range + * @h: the higher bound of the range + * + * time_before32(t, l, h) returns true if @l <= @t <= @h. All operands are + * treated as 32-bit integers. + * + * Equivalent to !(time_before32(@t, @l) || time_after32(@t, @h)). + */ +#define time_between32(t, l, h) ((u32)(h) - (u32)(l) >= (u32)(t) - (u32)(l)) #endif -- cgit v1.2.3