# git rev-parse -q --verify 1c27f1fc1549f0e470429f5497a76ad28a37f21a^{commit} 1c27f1fc1549f0e470429f5497a76ad28a37f21a already have revision, skipping fetch # git checkout -q -f -B kisskb 1c27f1fc1549f0e470429f5497a76ad28a37f21a # git clean -qxdf # < git log -1 # commit 1c27f1fc1549f0e470429f5497a76ad28a37f21a # Author: Linus Torvalds # Date: Sat Jun 11 10:30:20 2022 -0700 # # iov_iter: fix build issue due to possible type mis-match # # Commit 6c77676645ad ("iov_iter: Fix iter_xarray_get_pages{,_alloc}()") # introduced a problem on some 32-bit architectures (at least arm, xtensa, # csky,sparc and mips), that have a 'size_t' that is 'unsigned int'. # # The reason is that we now do # # min(nr * PAGE_SIZE - offset, maxsize); # # where 'nr' and 'offset' and both 'unsigned int', and PAGE_SIZE is # 'unsigned long'. As a result, the normal C type rules means that the # first argument to 'min()' ends up being 'unsigned long'. # # In contrast, 'maxsize' is of type 'size_t'. # # Now, 'size_t' and 'unsigned long' are always the same physical type in # the kernel, so you'd think this doesn't matter, and from an actual # arithmetic standpoint it doesn't. # # But on 32-bit architectures 'size_t' is commonly 'unsigned int', even if # it could also be 'unsigned long'. In that situation, both are unsigned # 32-bit types, but they are not the *same* type. # # And as a result 'min()' will complain about the distinct types (ignore # the "pointer types" part of the error message: that's an artifact of the # way we have made 'min()' check types for being the same): # # lib/iov_iter.c: In function 'iter_xarray_get_pages': # include/linux/minmax.h:20:35: error: comparison of distinct pointer types lacks a cast [-Werror] # 20 | (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1))) # | ^~ # lib/iov_iter.c:1464:16: note: in expansion of macro 'min' # 1464 | return min(nr * PAGE_SIZE - offset, maxsize); # | ^~~ # # This was not visible on 64-bit architectures (where we always define # 'size_t' to be 'unsigned long'). # # Force these cases to use 'min_t(size_t, x, y)' to make the type explicit # and avoid the issue. # # [ Nit-picky note: technically 'size_t' doesn't have to match 'unsigned # long' arithmetically. We've certainly historically seen environments # with 16-bit address spaces and 32-bit 'unsigned long'. # # Similarly, even in 64-bit modern environments, 'size_t' could be its # own type distinct from 'unsigned long', even if it were arithmetically # identical. # # So the above type commentary is only really descriptive of the kernel # environment, not some kind of universal truth for the kinds of wild # and crazy situations that are allowed by the C standard ] # # Reported-by: Sudip Mukherjee # Link: https://lore.kernel.org/all/YqRyL2sIqQNDfky2@debian/ # Cc: Jeff Layton # Cc: David Howells # Cc: Al Viro # Signed-off-by: Linus Torvalds # < /opt/cross/kisskb/korg/gcc-11.1.0-nolibc/m68k-linux/bin/m68k-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-11.1.0-nolibc/m68k-linux/bin/m68k-linux-ld --version # < git log --format=%s --max-count=1 1c27f1fc1549f0e470429f5497a76ad28a37f21a # < make -s -j 120 ARCH=m68k O=/kisskb/build/linus_sun3_defconfig_m68k-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/m68k-linux/bin/m68k-linux- sun3_defconfig arch/m68k/configs/sun3_defconfig:37:warning: symbol value 'm' invalid for ZPOOL # < make -s -j 120 ARCH=m68k O=/kisskb/build/linus_sun3_defconfig_m68k-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/m68k-linux/bin/m68k-linux- help # make -s -j 120 ARCH=m68k O=/kisskb/build/linus_sun3_defconfig_m68k-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/m68k-linux/bin/m68k-linux- olddefconfig # make -s -j 120 ARCH=m68k O=/kisskb/build/linus_sun3_defconfig_m68k-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/m68k-linux/bin/m68k-linux- In file included from /kisskb/src/include/linux/string.h:20, from /kisskb/src/include/linux/bitmap.h:11, from /kisskb/src/include/linux/cpumask.h:12, from /kisskb/src/include/linux/mm_types_task.h:14, from /kisskb/src/include/linux/mm_types.h:5, from /kisskb/src/include/linux/buildid.h:5, from /kisskb/src/include/linux/module.h:14, from /kisskb/src/drivers/net/ethernet/i825xx/sun3_82586.c:32: In function 'check586', inlined from 'sun3_82586_probe1' at /kisskb/src/drivers/net/ethernet/i825xx/sun3_82586.c:365:6, inlined from 'sun3_82586_probe' at /kisskb/src/drivers/net/ethernet/i825xx/sun3_82586.c:311:8: /kisskb/src/arch/m68k/include/asm/string.h:68:25: warning: '__builtin_memset' offset [0, 11] is out of the bounds [0, 0] [-Warray-bounds] 68 | #define memset(d, c, n) __builtin_memset(d, c, n) | ^~~~~~~~~~~~~~~~~~~~~~~~~ /kisskb/src/drivers/net/ethernet/i825xx/sun3_82586.c:218:9: note: in expansion of macro 'memset' 218 | memset((char *)p->scp,0, sizeof(struct scp_struct)); | ^~~~~~ In file included from /kisskb/src/include/linux/swab.h:5, from /kisskb/src/include/uapi/linux/byteorder/big_endian.h:14, from /kisskb/src/include/linux/byteorder/big_endian.h:5, from /kisskb/src/arch/m68k/include/uapi/asm/byteorder.h:5, from /kisskb/src/include/asm-generic/bitops/le.h:6, from /kisskb/src/arch/m68k/include/asm/bitops.h:529, from /kisskb/src/include/linux/bitops.h:33, from /kisskb/src/include/linux/kernel.h:22, from /kisskb/src/drivers/net/ethernet/i825xx/sun3_82586.c:31: /kisskb/src/drivers/net/ethernet/i825xx/sun3_82586.c: In function 'sun3_82586_timeout': /kisskb/src/drivers/net/ethernet/i825xx/sun3_82586.c:989:122: warning: array subscript 1 is above array bounds of 'volatile struct transmit_cmd_struct *[1]' [-Warray-bounds] 989 | printk("%s: command-stats: %04x %04x\n",dev->name,swab16(p->xmit_cmds[0]->cmd_status),swab16(p->xmit_cmds[1]->cmd_status)); | ~~~~~~~~~~~~^~~ /kisskb/src/include/uapi/linux/swab.h:107:19: note: in definition of macro '__swab16' 107 | __fswab16(x)) | ^ /kisskb/src/include/linux/printk.h:475:26: note: in expansion of macro 'printk_index_wrap' 475 | #define printk(fmt, ...) printk_index_wrap(_printk, fmt, ##__VA_ARGS__) | ^~~~~~~~~~~~~~~~~ /kisskb/src/drivers/net/ethernet/i825xx/sun3_82586.c:989:17: note: in expansion of macro 'printk' 989 | printk("%s: command-stats: %04x %04x\n",dev->name,swab16(p->xmit_cmds[0]->cmd_status),swab16(p->xmit_cmds[1]->cmd_status)); | ^~~~~~ /kisskb/src/drivers/net/ethernet/i825xx/sun3_82586.c:155:46: note: while referencing 'xmit_cmds' 155 | volatile struct transmit_cmd_struct *xmit_cmds[NUM_XMIT_BUFFS]; | ^~~~~~~~~ Completed OK # rm -rf /kisskb/build/linus_sun3_defconfig_m68k-gcc11 # Build took: 0:00:42.028574