# git rev-parse -q --verify 625d3449788f85569096780592549d0340e9c0c7^{commit}
625d3449788f85569096780592549d0340e9c0c7
already have revision, skipping fetch
# git checkout -q -f -B kisskb 625d3449788f85569096780592549d0340e9c0c7
# git clean -qxdf
# < git log -1
# commit 625d3449788f85569096780592549d0340e9c0c7
# Author: Jason A. Donenfeld <Jason@zx2c4.com>
# Date:   Sun Jun 21 21:02:22 2020 -0600
# 
#     Revert "kernel/printk: add kmsg SEEK_CUR handling"
#     
#     This reverts commit 8ece3b3eb576a78d2e67ad4c3a80a39fa6708809.
#     
#     This commit broke userspace. Bash uses ESPIPE to determine whether or
#     not the file should be read using "unbuffered I/O", which means reading
#     1 byte at a time instead of 128 bytes at a time. I used to use bash to
#     read through kmsg in a really quite nasty way:
#     
#         while read -t 0.1 -r line 2>/dev/null || [[ $? -ne 142 ]]; do
#            echo "SARU $line"
#         done < /dev/kmsg
#     
#     This will show all lines that can fit into the 128 byte buffer, and skip
#     lines that don't. That's pretty awful, but at least it worked.
#     
#     With this change, bash now tries to do 1-byte reads, which means it
#     skips all the lines, which is worse than before.
#     
#     Now, I don't really care very much about this, and I'm already look for
#     a workaround. But I did just spend an hour trying to figure out why my
#     scripts were broken. Either way, it makes no difference to me personally
#     whether this is reverted, but it might be something to consider. If you
#     declare that "trying to read /dev/kmsg with bash is terminally stupid
#     anyway," I might be inclined to agree with you. But do note that bash
#     uses lseek(fd, 0, SEEK_CUR)==>ESPIPE to determine whether or not it's
#     reading from a pipe.
#     
#     Cc: Bruno Meneguele <bmeneg@redhat.com>
#     Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
#     Cc: Steven Rostedt <rostedt@goodmis.org>
#     Cc: David Laight <David.Laight@ACULAB.COM>
#     Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
#     Cc: Petr Mladek <pmladek@suse.com>
#     Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/korg/gcc-10.1.0-nolibc/sh4-linux/bin/sh4-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-10.1.0-nolibc/sh4-linux/bin/sh4-linux-ld --version
# < git log --format=%s --max-count=1 625d3449788f85569096780592549d0340e9c0c7
# < make -s -j 24 ARCH=sh O=/kisskb/build/linus_se7619_defconfig_sh4-gcc10 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-10.1.0-nolibc/sh4-linux/bin/sh4-linux-  se7619_defconfig
# < make -s -j 24 ARCH=sh O=/kisskb/build/linus_se7619_defconfig_sh4-gcc10 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-10.1.0-nolibc/sh4-linux/bin/sh4-linux-  help
# make -s -j 24 ARCH=sh O=/kisskb/build/linus_se7619_defconfig_sh4-gcc10 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-10.1.0-nolibc/sh4-linux/bin/sh4-linux-  olddefconfig
# make -s -j 24 ARCH=sh O=/kisskb/build/linus_se7619_defconfig_sh4-gcc10 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-10.1.0-nolibc/sh4-linux/bin/sh4-linux-  
  Generating include/generated/machtypes.h
<stdin>:1511:2: warning: #warning syscall clone3 not implemented [-Wcpp]
/kisskb/src/arch/sh/kernel/cpu/sh2/../../entry-common.S: Assembler messages:
/kisskb/src/arch/sh/kernel/cpu/sh2/../../entry-common.S:385: Warning: overflow in branch to syscall_exit_work; converted into longer instruction sequence
/kisskb/src/arch/sh/kernel/cpu/sh2/../../entry-common.S:388: Warning: overflow in branch to syscall_exit_work; converted into longer instruction sequence
In file included from /kisskb/src/arch/sh/include/asm/hw_irq.h:6,
                 from /kisskb/src/include/linux/irq.h:563,
                 from /kisskb/src/arch/sh/include/asm/hardirq.h:6,
                 from /kisskb/src/include/linux/hardirq.h:10,
                 from /kisskb/src/include/linux/interrupt.h:11,
                 from /kisskb/src/include/linux/serial_core.h:14,
                 from /kisskb/src/include/linux/serial_sci.h:6,
                 from /kisskb/src/arch/sh/kernel/cpu/sh2/setup-sh7619.c:11:
/kisskb/src/include/linux/sh_intc.h:100:63: warning: division 'sizeof (void *) / sizeof (void)' does not compute the number of array elements [-Wsizeof-pointer-div]
  100 | #define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a)
      |                                                               ^
/kisskb/src/include/linux/sh_intc.h:105:24: note: in expansion of macro '_INTC_ARRAY'
  105 |  _INTC_ARRAY(vectors), _INTC_ARRAY(groups), \
      |                        ^~~~~~~~~~~
/kisskb/src/include/linux/sh_intc.h:124:8: note: in expansion of macro 'INTC_HW_DESC'
  124 |  .hw = INTC_HW_DESC(vectors, groups, mask_regs,   \
      |        ^~~~~~~~~~~~
/kisskb/src/arch/sh/kernel/cpu/sh2/setup-sh7619.c:58:8: note: in expansion of macro 'DECLARE_INTC_DESC'
   58 | static DECLARE_INTC_DESC(intc_desc, "sh7619", vectors, NULL,
      |        ^~~~~~~~~~~~~~~~~
/kisskb/src/include/linux/sh_intc.h:100:63: warning: division 'sizeof (void *) / sizeof (void)' does not compute the number of array elements [-Wsizeof-pointer-div]
  100 | #define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a)
      |                                                               ^
/kisskb/src/include/linux/sh_intc.h:106:2: note: in expansion of macro '_INTC_ARRAY'
  106 |  _INTC_ARRAY(mask_regs), _INTC_ARRAY(prio_regs), \
      |  ^~~~~~~~~~~
/kisskb/src/include/linux/sh_intc.h:124:8: note: in expansion of macro 'INTC_HW_DESC'
  124 |  .hw = INTC_HW_DESC(vectors, groups, mask_regs,   \
      |        ^~~~~~~~~~~~
/kisskb/src/arch/sh/kernel/cpu/sh2/setup-sh7619.c:58:8: note: in expansion of macro 'DECLARE_INTC_DESC'
   58 | static DECLARE_INTC_DESC(intc_desc, "sh7619", vectors, NULL,
      |        ^~~~~~~~~~~~~~~~~
/kisskb/src/include/linux/sh_intc.h:100:63: warning: division 'sizeof (void *) / sizeof (void)' does not compute the number of array elements [-Wsizeof-pointer-div]
  100 | #define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a)
      |                                                               ^
/kisskb/src/include/linux/sh_intc.h:107:2: note: in expansion of macro '_INTC_ARRAY'
  107 |  _INTC_ARRAY(sense_regs), _INTC_ARRAY(ack_regs), \
      |  ^~~~~~~~~~~
/kisskb/src/include/linux/sh_intc.h:124:8: note: in expansion of macro 'INTC_HW_DESC'
  124 |  .hw = INTC_HW_DESC(vectors, groups, mask_regs,   \
      |        ^~~~~~~~~~~~
/kisskb/src/arch/sh/kernel/cpu/sh2/setup-sh7619.c:58:8: note: in expansion of macro 'DECLARE_INTC_DESC'
   58 | static DECLARE_INTC_DESC(intc_desc, "sh7619", vectors, NULL,
      |        ^~~~~~~~~~~~~~~~~
/kisskb/src/include/linux/sh_intc.h:100:63: warning: division 'sizeof (void *) / sizeof (void)' does not compute the number of array elements [-Wsizeof-pointer-div]
  100 | #define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a)
      |                                                               ^
/kisskb/src/include/linux/sh_intc.h:107:27: note: in expansion of macro '_INTC_ARRAY'
  107 |  _INTC_ARRAY(sense_regs), _INTC_ARRAY(ack_regs), \
      |                           ^~~~~~~~~~~
/kisskb/src/include/linux/sh_intc.h:124:8: note: in expansion of macro 'INTC_HW_DESC'
  124 |  .hw = INTC_HW_DESC(vectors, groups, mask_regs,   \
      |        ^~~~~~~~~~~~
/kisskb/src/arch/sh/kernel/cpu/sh2/setup-sh7619.c:58:8: note: in expansion of macro 'DECLARE_INTC_DESC'
   58 | static DECLARE_INTC_DESC(intc_desc, "sh7619", vectors, NULL,
      |        ^~~~~~~~~~~~~~~~~
/kisskb/src/drivers/sh/clk/cpg.c: In function 'r8':
/kisskb/src/drivers/sh/clk/cpg.c:41:17: warning: passing argument 1 of 'ioread8' discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
   41 |  return ioread8(addr);
      |                 ^~~~
In file included from /kisskb/src/arch/sh/include/asm/io.h:21,
                 from /kisskb/src/include/linux/io.h:13,
                 from /kisskb/src/drivers/sh/clk/cpg.c:14:
/kisskb/src/include/asm-generic/iomap.h:29:29: note: expected 'void *' but argument is of type 'const void *'
   29 | extern unsigned int ioread8(void __iomem *);
      |                             ^~~~~~~~~~~~~~
/kisskb/src/drivers/sh/clk/cpg.c: In function 'r16':
/kisskb/src/drivers/sh/clk/cpg.c:46:18: warning: passing argument 1 of 'ioread16' discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
   46 |  return ioread16(addr);
      |                  ^~~~
In file included from /kisskb/src/arch/sh/include/asm/io.h:21,
                 from /kisskb/src/include/linux/io.h:13,
                 from /kisskb/src/drivers/sh/clk/cpg.c:14:
/kisskb/src/include/asm-generic/iomap.h:30:30: note: expected 'void *' but argument is of type 'const void *'
   30 | extern unsigned int ioread16(void __iomem *);
      |                              ^~~~~~~~~~~~~~
/kisskb/src/drivers/sh/clk/cpg.c: In function 'r32':
/kisskb/src/drivers/sh/clk/cpg.c:51:18: warning: passing argument 1 of 'ioread32' discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
   51 |  return ioread32(addr);
      |                  ^~~~
In file included from /kisskb/src/arch/sh/include/asm/io.h:21,
                 from /kisskb/src/include/linux/io.h:13,
                 from /kisskb/src/drivers/sh/clk/cpg.c:14:
/kisskb/src/include/asm-generic/iomap.h:32:30: note: expected 'void *' but argument is of type 'const void *'
   32 | extern unsigned int ioread32(void __iomem *);
      |                              ^~~~~~~~~~~~~~
Completed OK
# rm -rf /kisskb/build/linus_se7619_defconfig_sh4-gcc10
# Build took: 0:00:32.198544