# git rev-parse -q --verify 3593030761630e09200072a4bd06468892c27be3^{commit}
3593030761630e09200072a4bd06468892c27be3
already have revision, skipping fetch
# git checkout -q -f -B kisskb 3593030761630e09200072a4bd06468892c27be3
# git clean -qxdf
# < git log -1
# commit 3593030761630e09200072a4bd06468892c27be3
# Author: Linus Torvalds <torvalds@linux-foundation.org>
# Date:   Tue Feb 15 15:28:00 2022 -0800
# 
#     tty: n_tty: do not look ahead for EOL character past the end of the buffer
#     
#     Daniel Gibson reports that the n_tty code gets line termination wrong in
#     very specific cases:
#     
#      "If you feed a line with exactly 64 chars + terminating newline, and
#       directly afterwards (without reading) another line into a pseudo
#       terminal, the the first read() on the other side will return the 64
#       char line *without* terminating newline, and the next read() will
#       return the missing terminating newline AND the complete next line (if
#       it fits in the buffer)"
#     
#     and bisected the behavior to commit 3b830a9c34d5 ("tty: convert
#     tty_ldisc_ops 'read()' function to take a kernel pointer").
#     
#     Now, digging deeper, it turns out that the behavior isn't exactly new:
#     what changed in commit 3b830a9c34d5 was that the tty line discipline
#     .read() function is now passed an intermediate kernel buffer rather than
#     the final user space buffer.
#     
#     And that intermediate kernel buffer is 64 bytes in size - thus that
#     special case with exactly 64 bytes plus terminating newline.
#     
#     The same problem did exist before, but historically the boundary was not
#     the 64-byte chunk, but the user-supplied buffer size, which is obviously
#     generally bigger (and potentially bigger than N_TTY_BUF_SIZE, which
#     would hide the issue entirely).
#     
#     The reason is that the n_tty canon_copy_from_read_buf() code would look
#     ahead for the EOL character one byte further than it would actually
#     copy.  It would then decide that it had found the terminator, and unmark
#     it as an EOL character - which in turn explains why the next read
#     wouldn't then be terminated by it.
#     
#     Now, the reason it did all this in the first place is related to some
#     historical and pretty obscure EOF behavior, see commit ac8f3bf8832a
#     ("n_tty: Fix poll() after buffer-limited eof push read") and commit
#     40d5e0905a03 ("n_tty: Fix EOF push handling").
#     
#     And the reason for the EOL confusion is that we treat EOF as a special
#     EOL condition, with the EOL character being NUL (aka "__DISABLED_CHAR"
#     in the kernel sources).
#     
#     So that EOF look-ahead also affects the normal EOL handling.
#     
#     This patch just removes the look-ahead that causes problems, because EOL
#     is much more critical than the historical "EOF in the middle of a line
#     that coincides with the end of the buffer" handling ever was.
#     
#     Now, it is possible that we should indeed re-introduce the "look at next
#     character to see if it's a EOF" behavior, but if so, that should be done
#     not at the kernel buffer chunk boundary in canon_copy_from_read_buf(),
#     but at a higher level, when we run out of the user buffer.
#     
#     In particular, the place to do that would be at the top of
#     'n_tty_read()', where we check if it's a continuation of a previously
#     started read, and there is no more buffer space left, we could decide to
#     just eat the __DISABLED_CHAR at that point.
#     
#     But that would be a separate patch, because I suspect nobody actually
#     cares, and I'd like to get a report about it before bothering.
#     
#     Fixes: 3b830a9c34d5 ("tty: convert tty_ldisc_ops 'read()' function to take a kernel pointer")
#     Fixes: ac8f3bf8832a ("n_tty: Fix  poll() after buffer-limited eof push read")
#     Fixes: 40d5e0905a03 ("n_tty: Fix EOF push handling")
#     Link: https://bugzilla.kernel.org/show_bug.cgi?id=215611
#     Reported-and-tested-by: Daniel Gibson <metalcaedes@gmail.com>
#     Cc: Peter Hurley <peter@hurleysoftware.com>
#     Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
#     Cc: Jiri Slaby <jirislaby@kernel.org>
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/korg/gcc-11.1.0-nolibc/xtensa-linux/bin/xtensa-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-11.1.0-nolibc/xtensa-linux/bin/xtensa-linux-ld --version
# < git log --format=%s --max-count=1 3593030761630e09200072a4bd06468892c27be3
# < make -s -j 24 ARCH=xtensa O=/kisskb/build/linus_xtensa-allmodconfig_xtensa-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/xtensa-linux/bin/xtensa-linux-  allmodconfig
# Added to kconfig CONFIG_BUILD_DOCSRC=n
# Added to kconfig CONFIG_MODULE_SIG=n
# Added to kconfig CONFIG_SAMPLES=n
# < make -s -j 24 ARCH=xtensa O=/kisskb/build/linus_xtensa-allmodconfig_xtensa-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/xtensa-linux/bin/xtensa-linux-  help
# make -s -j 24 ARCH=xtensa O=/kisskb/build/linus_xtensa-allmodconfig_xtensa-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/xtensa-linux/bin/xtensa-linux-  olddefconfig
# make -s -j 24 ARCH=xtensa O=/kisskb/build/linus_xtensa-allmodconfig_xtensa-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/xtensa-linux/bin/xtensa-linux-  
/kisskb/src/arch/xtensa/boot/dts/xtfpga-flash-128m.dtsi:11.18-14.6: Warning (unit_address_format): /soc/flash@00000000/partition@0x0: unit name should not have leading "0x"
/kisskb/src/arch/xtensa/boot/dts/xtfpga-flash-128m.dtsi:15.24-18.6: Warning (unit_address_format): /soc/flash@00000000/partition@0x6000000: unit name should not have leading "0x"
/kisskb/src/arch/xtensa/boot/dts/xtfpga-flash-128m.dtsi:19.24-22.6: Warning (unit_address_format): /soc/flash@00000000/partition@0x6800000: unit name should not have leading "0x"
/kisskb/src/arch/xtensa/boot/dts/xtfpga-flash-128m.dtsi:23.24-26.6: Warning (unit_address_format): /soc/flash@00000000/partition@0x7fe0000: unit name should not have leading "0x"
/kisskb/src/arch/xtensa/boot/dts/xtfpga-flash-128m.dtsi:11.18-14.6: Warning (unit_address_format): /soc/flash@00000000/partition@0x0: unit name should not have leading "0x"
/kisskb/src/arch/xtensa/boot/dts/xtfpga-flash-128m.dtsi:15.24-18.6: Warning (unit_address_format): /soc/flash@00000000/partition@0x6000000: unit name should not have leading "0x"
/kisskb/src/arch/xtensa/boot/dts/xtfpga-flash-128m.dtsi:19.24-22.6: Warning (unit_address_format): /soc/flash@00000000/partition@0x6800000: unit name should not have leading "0x"
/kisskb/src/arch/xtensa/boot/dts/xtfpga-flash-128m.dtsi:23.24-26.6: Warning (unit_address_format): /soc/flash@00000000/partition@0x7fe0000: unit name should not have leading "0x"
/kisskb/src/arch/xtensa/boot/dts/xtfpga-flash-16m.dtsi:11.18-14.6: Warning (unit_address_format): /soc/flash@08000000/partition@0x0: unit name should not have leading "0x"
/kisskb/src/arch/xtensa/boot/dts/xtfpga-flash-16m.dtsi:15.23-18.6: Warning (unit_address_format): /soc/flash@08000000/partition@0x400000: unit name should not have leading "0x"
/kisskb/src/arch/xtensa/boot/dts/xtfpga-flash-16m.dtsi:19.23-22.6: Warning (unit_address_format): /soc/flash@08000000/partition@0xa00000: unit name should not have leading "0x"
/kisskb/src/arch/xtensa/boot/dts/xtfpga-flash-16m.dtsi:11.18-14.6: Warning (unit_address_format): /soc/flash@08000000/partition@0x0: unit name should not have leading "0x"
/kisskb/src/arch/xtensa/boot/dts/xtfpga-flash-16m.dtsi:23.23-26.6: Warning (unit_address_format): /soc/flash@08000000/partition@0xfe0000: unit name should not have leading "0x"
/kisskb/src/arch/xtensa/boot/dts/xtfpga-flash-16m.dtsi:15.23-18.6: Warning (unit_address_format): /soc/flash@08000000/partition@0x400000: unit name should not have leading "0x"
/kisskb/src/arch/xtensa/boot/dts/xtfpga-flash-16m.dtsi:19.23-22.6: Warning (unit_address_format): /soc/flash@08000000/partition@0xa00000: unit name should not have leading "0x"
/kisskb/src/arch/xtensa/boot/dts/xtfpga-flash-16m.dtsi:23.23-26.6: Warning (unit_address_format): /soc/flash@08000000/partition@0xfe0000: unit name should not have leading "0x"
/kisskb/src/arch/xtensa/boot/dts/xtfpga-flash-4m.dtsi:11.18-14.6: Warning (unit_address_format): /soc/flash@08000000/partition@0x0: unit name should not have leading "0x"
/kisskb/src/arch/xtensa/boot/dts/xtfpga-flash-4m.dtsi:15.23-18.6: Warning (unit_address_format): /soc/flash@08000000/partition@0x3f0000: unit name should not have leading "0x"
WARNING: modpost: vmlinux.o(.text.unlikely+0x4540): Section mismatch in reference from the function __trace_event_discard_commit() to the variable .init.data:initcall_level_names
The function __trace_event_discard_commit() references
the variable __initdata initcall_level_names.
This is often because __trace_event_discard_commit lacks a __initdata 
annotation or the annotation of initcall_level_names is wrong.

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x14410): Section mismatch in reference from the variable qed_mfw_legacy_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_legacy_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x14428): Section mismatch in reference from the variable qed_mfw_legacy_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_legacy_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x14440): Section mismatch in reference from the variable qed_mfw_legacy_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_legacy_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x14458): Section mismatch in reference from the variable qed_mfw_legacy_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_legacy_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x14470): Section mismatch in reference from the variable qed_mfw_legacy_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_legacy_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x14488): Section mismatch in reference from the variable qed_mfw_legacy_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_legacy_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x144a0): Section mismatch in reference from the variable qed_mfw_legacy_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_legacy_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x144f0): Section mismatch in reference from the variable qed_mfw_ext_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_ext_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x14508): Section mismatch in reference from the variable qed_mfw_ext_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_ext_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x14520): Section mismatch in reference from the variable qed_mfw_ext_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_ext_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x14538): Section mismatch in reference from the variable qed_mfw_ext_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_ext_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x14550): Section mismatch in reference from the variable qed_mfw_ext_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_ext_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x14568): Section mismatch in reference from the variable qed_mfw_ext_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_ext_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x14580): Section mismatch in reference from the variable qed_mfw_ext_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_ext_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qed/qed.o(.data+0x14598): Section mismatch in reference from the variable qed_mfw_ext_maps to the variable .init.rodata:qed_mfw_legacy_bb_100g
The variable qed_mfw_ext_maps references
the variable __initconst qed_mfw_legacy_bb_100g
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qede/qede.o(.data+0x4790): Section mismatch in reference from the variable qede_forced_speed_maps to the variable .init.rodata:qede_forced_speed_100000
The variable qede_forced_speed_maps references
the variable __initconst qede_forced_speed_100000
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qede/qede.o(.data+0x47a8): Section mismatch in reference from the variable qede_forced_speed_maps to the variable .init.rodata:qede_forced_speed_100000
The variable qede_forced_speed_maps references
the variable __initconst qede_forced_speed_100000
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qede/qede.o(.data+0x47c0): Section mismatch in reference from the variable qede_forced_speed_maps to the variable .init.rodata:qede_forced_speed_100000
The variable qede_forced_speed_maps references
the variable __initconst qede_forced_speed_100000
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qede/qede.o(.data+0x47d8): Section mismatch in reference from the variable qede_forced_speed_maps to the variable .init.rodata:qede_forced_speed_100000
The variable qede_forced_speed_maps references
the variable __initconst qede_forced_speed_100000
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qede/qede.o(.data+0x47f0): Section mismatch in reference from the variable qede_forced_speed_maps to the variable .init.rodata:qede_forced_speed_100000
The variable qede_forced_speed_maps references
the variable __initconst qede_forced_speed_100000
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qede/qede.o(.data+0x4808): Section mismatch in reference from the variable qede_forced_speed_maps to the variable .init.rodata:qede_forced_speed_100000
The variable qede_forced_speed_maps references
the variable __initconst qede_forced_speed_100000
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: modpost: drivers/net/ethernet/qlogic/qede/qede.o(.data+0x4820): Section mismatch in reference from the variable qede_forced_speed_maps to the variable .init.rodata:qede_forced_speed_100000
The variable qede_forced_speed_maps references
the variable __initconst qede_forced_speed_100000
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

Completed OK
# rm -rf /kisskb/build/linus_xtensa-allmodconfig_xtensa-gcc11
# Build took: 0:29:27.613660