From 5e322beefc8699b5747cfb35539a9496034e4296 Mon Sep 17 00:00:00 2001 From: Vlastimil Babka Date: Thu, 10 Nov 2016 10:46:07 -0800 Subject: mm, frontswap: make sure allocated frontswap map is assigned Christian Borntraeger reports: With commit 8ea1d2a1985a ("mm, frontswap: convert frontswap_enabled to static key") kmemleak complains about a memory leak in swapon unreferenced object 0x3e09ba56000 (size 32112640): comm "swapon", pid 7852, jiffies 4294968787 (age 1490.770s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: __vmalloc_node_range+0x194/0x2d8 vzalloc+0x58/0x68 SyS_swapon+0xd60/0x12f8 system_call+0xd6/0x270 Turns out kmemleak is right. We now allocate the frontswap map depending on the kernel config (and no longer on the enablement) swapfile.c: [...] if (IS_ENABLED(CONFIG_FRONTSWAP)) frontswap_map = vzalloc(BITS_TO_LONGS(maxpages) * sizeof(long)); but later on this is passed along --> enable_swap_info(p, prio, swap_map, cluster_info, frontswap_map); and ignored if frontswap is disabled --> frontswap_init(p->type, frontswap_map); static inline void frontswap_init(unsigned type, unsigned long *map) { if (frontswap_enabled()) __frontswap_init(type, map); } Thing is, that frontswap map is never freed. The leakage is relatively not that bad, because swapon is an infrequent and privileged operation. However, if the first frontswap backend is registered after a swap type has been already enabled, it will WARN_ON in frontswap_register_ops() and frontswap will not be available for the swap type. Fix this by making sure the map is assigned by frontswap_init() as long as CONFIG_FRONTSWAP is enabled. Fixes: 8ea1d2a1985a ("mm, frontswap: convert frontswap_enabled to static key") Link: http://lkml.kernel.org/r/20161026134220.2566-1-vbabka@suse.cz Signed-off-by: Vlastimil Babka Reported-by: Christian Borntraeger Cc: Konrad Rzeszutek Wilk Cc: Boris Ostrovsky Cc: David Vrabel Cc: Juergen Gross Cc: "Kirill A. Shutemov" Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/frontswap.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/frontswap.h b/include/linux/frontswap.h index c46d2aa16d81..1d18af034554 100644 --- a/include/linux/frontswap.h +++ b/include/linux/frontswap.h @@ -106,8 +106,9 @@ static inline void frontswap_invalidate_area(unsigned type) static inline void frontswap_init(unsigned type, unsigned long *map) { - if (frontswap_enabled()) - __frontswap_init(type, map); +#ifdef CONFIG_FRONTSWAP + __frontswap_init(type, map); +#endif } #endif /* _LINUX_FRONTSWAP_H */ -- cgit v1.2.3 From c6c7d83b9c9e6a8b3e6d84c820ac61fbffc9e396 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Thu, 10 Nov 2016 10:46:26 -0800 Subject: Revert "console: don't prefer first registered if DT specifies stdout-path" This reverts commit 05fd007e4629 ("console: don't prefer first registered if DT specifies stdout-path"). The reverted commit changes existing behavior on which many ARM boards rely. Many ARM small-board-computers, like e.g. the Raspberry Pi have both a video output and a serial console. Depending on whether the user is using the device as a more regular computer; or as a headless device we need to have the console on either one or the other. Many users rely on the kernel behavior of the console being present on both outputs, before the reverted commit the console setup with no console= kernel arguments on an ARM board which sets stdout-path in dt would look like this: [root@localhost ~]# cat /proc/consoles ttyS0 -W- (EC p a) 4:64 tty0 -WU (E p ) 4:1 Where as after the reverted commit, it looks like this: [root@localhost ~]# cat /proc/consoles ttyS0 -W- (EC p a) 4:64 This commit reverts commit 05fd007e4629 ("console: don't prefer first registered if DT specifies stdout-path") restoring the original behavior. Fixes: 05fd007e4629 ("console: don't prefer first registered if DT specifies stdout-path") Link: http://lkml.kernel.org/r/20161104121135.4780-2-hdegoede@redhat.com Signed-off-by: Hans de Goede Cc: Paul Burton Cc: Rob Herring Cc: Frank Rowand Cc: Thorsten Leemhuis Cc: Greg Kroah-Hartman Cc: Tejun Heo Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/of/base.c | 2 -- include/linux/console.h | 6 ------ kernel/printk/printk.c | 13 +------------ 3 files changed, 1 insertion(+), 20 deletions(-) (limited to 'include/linux') diff --git a/drivers/of/base.c b/drivers/of/base.c index d687e6de24a0..a0bccb54a9bd 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -2077,8 +2077,6 @@ void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align)) name = of_get_property(of_aliases, "stdout", NULL); if (name) of_stdout = of_find_node_opts_by_path(name, &of_stdout_options); - if (of_stdout) - console_set_by_of(); } if (!of_aliases) diff --git a/include/linux/console.h b/include/linux/console.h index 3672809234a7..d530c4627e54 100644 --- a/include/linux/console.h +++ b/include/linux/console.h @@ -173,12 +173,6 @@ static inline void console_sysfs_notify(void) #endif extern bool console_suspend_enabled; -#ifdef CONFIG_OF -extern void console_set_by_of(void); -#else -static inline void console_set_by_of(void) {} -#endif - /* Suspend and resume console messages over PM events */ extern void suspend_console(void); extern void resume_console(void); diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index de08fc90baaf..5028f4fd504a 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -253,17 +253,6 @@ static int preferred_console = -1; int console_set_on_cmdline; EXPORT_SYMBOL(console_set_on_cmdline); -#ifdef CONFIG_OF -static bool of_specified_console; - -void console_set_by_of(void) -{ - of_specified_console = true; -} -#else -# define of_specified_console false -#endif - /* Flag: console code may call schedule() */ static int console_may_schedule; @@ -2657,7 +2646,7 @@ void register_console(struct console *newcon) * didn't select a console we take the first one * that registers here. */ - if (preferred_console < 0 && !of_specified_console) { + if (preferred_console < 0) { if (newcon->index < 0) newcon->index = 0; if (newcon->setup == NULL || -- cgit v1.2.3