From 3ca45a46f8af8c4a92dd8a08eac57787242d5021 Mon Sep 17 00:00:00 2001 From: zijun_hu Date: Fri, 14 Oct 2016 15:12:54 +0800 Subject: percpu: ensure the requested alignment is power of two The percpu allocator expectedly assumes that the requested alignment is power of two but hasn't been veryfing the input. If the specified alignment isn't power of two, the allocator can malfunction. Add the sanity check. The following is detailed analysis of the effects of alignments which aren't power of two. The alignment must be a even at least since the LSB of a chunk->map element is used as free/in-use flag of a area; besides, the alignment must be a power of 2 too since ALIGN() doesn't work well for other alignment always but is adopted by pcpu_fit_in_area(). IOW, the current allocator only works well for a power of 2 aligned area allocation. See below opposite example for why an odd alignment doesn't work. Let's assume area [16, 36) is free but its previous one is in-use, we want to allocate a @size == 8 and @align == 7 area. The larger area [16, 36) is split to three areas [16, 21), [21, 29), [29, 36) eventually. However, due to the usage for a chunk->map element, the actual offset of the aim area [21, 29) is 21 but is recorded in relevant element as 20; moreover, the residual tail free area [29, 36) is mistook as in-use and is lost silently Unlike macro roundup(), ALIGN(x, a) doesn't work if @a isn't a power of 2 for example, roundup(10, 6) == 12 but ALIGN(10, 6) == 10, and the latter result isn't desired obviously. tj: Code style and patch description updates. Signed-off-by: zijun_hu Suggested-by: Tejun Heo Signed-off-by: Tejun Heo --- include/linux/kernel.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index bc6ed52a39b9..0dc0b21bd164 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -45,6 +45,7 @@ #define REPEAT_BYTE(x) ((~0ul / 0xff) * (x)) +/* @a is a power of 2 value */ #define ALIGN(x, a) __ALIGN_KERNEL((x), (a)) #define __ALIGN_MASK(x, mask) __ALIGN_KERNEL_MASK((x), (mask)) #define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a))) -- cgit v1.2.3 From d38499530e5f170d30f32d3841fade204e63081d Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 1 Nov 2016 07:40:11 -0600 Subject: fs: decouple READ and WRITE from the block layer ops Move READ and WRITE to kernel.h and don't define them in terms of block layer ops; they are our generic data direction indicators these days and have no more resemblance with the block layer ops. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- include/linux/kernel.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index bc6ed52a39b9..01b6b460c34d 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -50,6 +50,10 @@ #define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a))) #define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0) +/* generic data direction definitions */ +#define READ 0 +#define WRITE 1 + #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr)) #define u64_to_user_ptr(x) ( \ -- cgit v1.2.3 From 7fd8329ba502ef76dd91db561c7aed696b2c7720 Mon Sep 17 00:00:00 2001 From: Petr Mladek Date: Wed, 21 Sep 2016 13:47:22 +0200 Subject: taint/module: Clean up global and module taint flags handling The commit 66cc69e34e86a231 ("Fix: module signature vs tracepoints: add new TAINT_UNSIGNED_MODULE") updated module_taint_flags() to potentially print one more character. But it did not increase the size of the corresponding buffers in m_show() and print_modules(). We have recently done the same mistake when adding a taint flag for livepatching, see https://lkml.kernel.org/r/cfba2c823bb984690b73572aaae1db596b54a082.1472137475.git.jpoimboe@redhat.com Also struct module uses an incompatible type for mod-taints flags. It survived from the commit 2bc2d61a9638dab670d ("[PATCH] list module taint flags in Oops/panic"). There was used "int" for the global taint flags at these times. But only the global tain flags was later changed to "unsigned long" by the commit 25ddbb18aae33ad2 ("Make the taint flags reliable"). This patch defines TAINT_FLAGS_COUNT that can be used to create arrays and buffers of the right size. Note that we could not use enum because the taint flag indexes are used also in assembly code. Then it reworks the table that describes the taint flags. The TAINT_* numbers can be used as the index. Instead, we add information if the taint flag is also shown per-module. Finally, it uses "unsigned long", bit operations, and the updated taint_flags table also for mod->taints. It is not optimal because only few taint flags can be printed by module_taint_flags(). But better be on the safe side. IMHO, it is not worth the optimization and this is a good compromise. Signed-off-by: Petr Mladek Link: http://lkml.kernel.org/r/1474458442-21581-1-git-send-email-pmladek@suse.com [jeyu@redhat.com: fix broken lkml link in changelog] Signed-off-by: Jessica Yu --- include/linux/kernel.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index bc6ed52a39b9..441def77246d 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -506,6 +506,15 @@ extern enum system_states { #define TAINT_UNSIGNED_MODULE 13 #define TAINT_SOFTLOCKUP 14 #define TAINT_LIVEPATCH 15 +#define TAINT_FLAGS_COUNT 16 + +struct taint_flag { + char true; /* character printed when tainted */ + char false; /* character printed when not tainted */ + bool module; /* also show as a per-module taint flag */ +}; + +extern const struct taint_flag taint_flags[TAINT_FLAGS_COUNT]; extern const char hex_asc[]; #define hex_asc_lo(x) hex_asc[((x) & 0x0f)] -- cgit v1.2.3 From 5eb7c0d04f04a667c049fe090a95494a8de2955c Mon Sep 17 00:00:00 2001 From: Larry Finger Date: Sun, 1 Jan 2017 20:25:25 -0600 Subject: taint/module: Fix problems when out-of-kernel driver defines true or false Commit 7fd8329ba502 ("taint/module: Clean up global and module taint flags handling") used the key words true and false as character members of a new struct. These names cause problems when out-of-kernel modules such as VirtualBox include their own definitions of true and false. Fixes: 7fd8329ba502 ("taint/module: Clean up global and module taint flags handling") Signed-off-by: Larry Finger Cc: Petr Mladek Cc: Jessica Yu Cc: Rusty Russell Reported-by: Valdis Kletnieks Reviewed-by: Petr Mladek Acked-by: Rusty Russell Signed-off-by: Jessica Yu --- include/linux/kernel.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 56aec84237ad..cb09238f6d32 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -514,8 +514,8 @@ extern enum system_states { #define TAINT_FLAGS_COUNT 16 struct taint_flag { - char true; /* character printed when tainted */ - char false; /* character printed when not tainted */ + char c_true; /* character printed when tainted */ + char c_false; /* character printed when not tainted */ bool module; /* also show as a per-module taint flag */ }; -- cgit v1.2.3