GCC/ARM experts wanted [Was: Re: include/linux/compiler_types.h:397:45: error: call to '__compiletime_assert_460' declared with attribute error: BUILD_BUG_ON failed: sizeof(vring->va[0]) != 32]

From: Dmitry Antipov
Date: Wed Nov 15 2023 - 06:23:14 EST


On 11/15/23 03:49, kernel test robot wrote:

tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 9bacdd8996c77c42ca004440be610692275ff9d0
commit: 1ad8237e971630c66a1a6194491e0837b64d00e0 wifi: wil6210: fix fortify warnings
date: 4 months ago
config: arm-buildonly-randconfig-r003-20220914 (https://download.01.org/0day-ci/archive/20231115/202311150821.cI4yciFE-lkp@xxxxxxxxx/config)
compiler: arm-linux-gnueabi-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231115/202311150821.cI4yciFE-lkp@xxxxxxxxx/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202311150821.cI4yciFE-lkp@xxxxxxxxx/

All errors (new ones prefixed by >>):

In file included from <command-line>:
drivers/net/wireless/ath/wil6210/txrx.c: In function 'wil_vring_alloc':
include/linux/compiler_types.h:397:45: error: call to '__compiletime_assert_460' declared with attribute error: BUILD_BUG_ON failed: sizeof(vring->va[0]) != 32
397 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^
include/linux/compiler_types.h:378:25: note: in definition of macro '__compiletime_assert'
378 | prefix ## suffix(); \
| ^~~~~~
include/linux/compiler_types.h:397:9: note: in expansion of macro '_compiletime_assert'
397 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
| ^~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:50:9: note: in expansion of macro 'BUILD_BUG_ON_MSG'
50 | BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
| ^~~~~~~~~~~~~~~~
drivers/net/wireless/ath/wil6210/txrx.c:118:9: note: in expansion of macro 'BUILD_BUG_ON'
118 | BUILD_BUG_ON(sizeof(vring->va[0]) != 32);
| ^~~~~~~~~~~~
--
In file included from <command-line>:
drivers/net/wireless/ath/wil6210/txrx_edma.c: In function 'wil_ring_alloc_desc_ring':
include/linux/compiler_types.h:397:45: error: call to '__compiletime_assert_452' declared with attribute error: BUILD_BUG_ON failed: sizeof(ring->va[0]) != 32
397 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^
include/linux/compiler_types.h:378:25: note: in definition of macro '__compiletime_assert'
378 | prefix ## suffix(); \
| ^~~~~~
include/linux/compiler_types.h:397:9: note: in expansion of macro '_compiletime_assert'
397 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
| ^~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:50:9: note: in expansion of macro 'BUILD_BUG_ON_MSG'
50 | BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
| ^~~~~~~~~~~~~~~~
drivers/net/wireless/ath/wil6210/txrx_edma.c:381:9: note: in expansion of macro 'BUILD_BUG_ON'
381 | BUILD_BUG_ON(sizeof(ring->va[0]) != 32);
| ^~~~~~~~~~~~


vim +/__compiletime_assert_460 +397 include/linux/compiler_types.h

eb5c2d4b45e3d2 Will Deacon 2020-07-21 383
eb5c2d4b45e3d2 Will Deacon 2020-07-21 384 #define _compiletime_assert(condition, msg, prefix, suffix) \
eb5c2d4b45e3d2 Will Deacon 2020-07-21 385 __compiletime_assert(condition, msg, prefix, suffix)
eb5c2d4b45e3d2 Will Deacon 2020-07-21 386
eb5c2d4b45e3d2 Will Deacon 2020-07-21 387 /**
eb5c2d4b45e3d2 Will Deacon 2020-07-21 388 * compiletime_assert - break build and emit msg if condition is false
eb5c2d4b45e3d2 Will Deacon 2020-07-21 389 * @condition: a compile-time constant condition to check
eb5c2d4b45e3d2 Will Deacon 2020-07-21 390 * @msg: a message to emit if condition is false
eb5c2d4b45e3d2 Will Deacon 2020-07-21 391 *
eb5c2d4b45e3d2 Will Deacon 2020-07-21 392 * In tradition of POSIX assert, this macro will break the build if the
eb5c2d4b45e3d2 Will Deacon 2020-07-21 393 * supplied condition is *false*, emitting the supplied error message if the
eb5c2d4b45e3d2 Will Deacon 2020-07-21 394 * compiler has support to do so.
eb5c2d4b45e3d2 Will Deacon 2020-07-21 395 */
eb5c2d4b45e3d2 Will Deacon 2020-07-21 396 #define compiletime_assert(condition, msg) \
eb5c2d4b45e3d2 Will Deacon 2020-07-21 @397 _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
eb5c2d4b45e3d2 Will Deacon 2020-07-21 398

:::::: The code at line 397 was first introduced by commit
:::::: eb5c2d4b45e3d2d5d052ea6b8f1463976b1020d5 compiler.h: Move compiletime_assert() macros into compiler_types.h

:::::: TO: Will Deacon <will@xxxxxxxxxx>
:::::: CC: Will Deacon <will@xxxxxxxxxx>

I've tracked this down to the following sample:

struct vring_tx_mac {
unsigned int d[3];
unsigned int ucode_cmd;
} __attribute__((packed));

struct vring_rx_mac {
unsigned int d0;
unsigned int d1;
unsigned short w4;
union { struct { unsigned short pn_15_0; unsigned int pn_47_16; } __attribute__((__packed__));
struct { unsigned short pn_15_0; unsigned int pn_47_16; } __attribute__((__packed__)) pn;
};
} __attribute__((packed));

struct wil_ring_dma_addr {
unsigned int addr_low;
unsigned short addr_high;
} __attribute__((packed));

struct vring_tx_dma {
unsigned int d0;
struct wil_ring_dma_addr addr;
unsigned char ip_length;
unsigned char b11; /* 0..6: mac_length; 7:ip_version */
unsigned char error; /* 0..2: err; 3..7: reserved; */
unsigned char status; /* 0: used; 1..7; reserved */
unsigned short length;
} __packed;

struct vring_tx_desc {
struct vring_tx_mac mac;
struct vring_tx_dma dma;
} __attribute__((packed));

struct wil_ring_tx_enhanced_mac {
unsigned int d[3];
unsigned short tso_mss;
unsigned short scratchpad;
} __attribute__((packed));

struct wil_ring_tx_enhanced_dma {
unsigned char l4_hdr_len;
unsigned char cmd;
unsigned short w1;
struct wil_ring_dma_addr addr;
unsigned char ip_length;
unsigned char b11; /* 0..6: mac_length; 7:ip_version */
unsigned short addr_high_high;
unsigned short length;
} __attribute__((packed));

struct wil_tx_enhanced_desc {
struct wil_ring_tx_enhanced_mac mac;
struct wil_ring_tx_enhanced_dma dma;
} __attribute__((packed));

union wil_tx_desc {
struct vring_tx_desc legacy;
struct wil_tx_enhanced_desc enhanced;
} __attribute__((packed));

struct vring_rx_dma {
unsigned int d0;
struct wil_ring_dma_addr addr;
unsigned char ip_length;
unsigned char b11;
unsigned char error;
unsigned char status;
unsigned short length;
} __attribute__((packed));

struct vring_rx_desc {
struct vring_rx_mac mac;
struct vring_rx_dma dma;
} __attribute__((packed));

struct wil_ring_rx_enhanced_mac {
unsigned int d[3];
unsigned short buff_id;
unsigned short reserved;
} __attribute((packed));

struct wil_ring_rx_enhanced_dma {
unsigned int d0;
struct wil_ring_dma_addr addr;
unsigned short w5;
unsigned short addr_high_high;
unsigned short length;
} __attribute((packed));

struct wil_rx_enhanced_desc {
struct wil_ring_rx_enhanced_mac mac;
struct wil_ring_rx_enhanced_dma dma;
} __attribute((packed));

union wil_rx_desc {
struct vring_rx_desc legacy;
struct wil_rx_enhanced_desc enhanced;
} __attribute__((packed));

union wil_ring_desc {
union wil_tx_desc tx;
union wil_rx_desc rx;
} __attribute__((packed));

int f (void) {
return sizeof(union wil_ring_desc);
}

$ arm-linux-gnu-gcc -Os -c t-build-bug.c
$ arm-linux-gnu-objdump -j .text -D t-build-bug.o

t-build-bug.o: file format elf32-littlearm

Disassembly of section .text:

00000000 <f>:
0: e3a00020 mov r0, #32 ;; OK
4: e12fff1e bx lr

$ arm-linux-gnu-gcc -mlittle-endian -std=gnu11 -fshort-wchar -funsigned-char -fno-common -fno-PIE -fno-strict-aliasing -fno-dwarf2-cfi-asm -mno-fdpic -fno-omit-frame-pointer -mapcs -mno-sched-prolog -fno-ipa-sra -mabi=apcs-gnu -mno-thumb-interwork -marm -Wa,-mno-warn-deprecated -march=armv4 -mtune=xscale -msoft-float -Uarm -fno-delete-null-pointer-checks -Os -fno-allow-store-data-races -fno-reorder-blocks -fno-ipa-cp-clone -fno-partial-inlining -fno-stack-protector -fno-omit-frame-pointer -fno-optimize-sibling-calls -ftrivial-auto-var-init=zero -fno-stack-clash-protection -pg -fno-inline-functions-called-once -fstrict-flex-arrays=3 -fno-strict-overflow -fno-stack-check -fconserve-stack -fsanitize=kernel-address -fasan-shadow-offset=0x1f000000 --param asan-globals=1 --param asan-instrumentation-with-call-threshold=10000 --param asan-instrument-allocas=1 --param asan-stack=1 --param asan-kernel-mem-intrinsic-prefix=1 -c t-build-bug.c
$ arm-linux-gnu-objdump -j .text -D t-build-bug.o

t-build-bug.o: file format elf32-littlearm

Disassembly of section .text:

00000000 <f>:
0: e1a0c00d mov ip, sp
4: e92dd800 push {fp, ip, lr, pc}
8: e24cb004 sub fp, ip, #4
c: e52de004 push {lr} @ (str lr, [sp, #-4]!)
10: ebfffffe bl 0 <__gnu_mcount_nc>
14: e3a00022 mov r0, #34 @ 0x22 ;; OOPS
18: e89da800 ldm sp, {fp, sp, pc}

Now it's time for advice from GCC/ARM experts.

Dmitry