28 Nov, 2020
1 commit
-
Pull printk fixes from Petr Mladek:
- do not lose trailing newline in pr_cont() calls
- two trivial fixes for a dead store and a config description
* tag 'printk-for-5.10-rc6-fixup' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
printk: finalize records with trailing newlines
printk: remove unneeded dead-store assignment
init/Kconfig: Fix CPU number in LOG_CPU_MAX_BUF_SHIFT description
27 Nov, 2020
2 commits
-
Any record with a trailing newline (LOG_NEWLINE flag) cannot
be continued because the newline has been stripped and will
not be visible if the message is appended. This was already
handled correctly when committing in log_output() but was
not handled correctly when committing in log_store().Fixes: f5f022e53b87 ("printk: reimplement log_cont using record extension")
Link: https://lore.kernel.org/r/20201126114836.14750-1-john.ogness@linutronix.de
Reported-by: Kefeng Wang
Signed-off-by: John Ogness
Tested-by: Kefeng Wang
Reviewed-by: Petr Mladek
Signed-off-by: Petr Mladek
06 Nov, 2020
1 commit
-
make clang-analyzer on x86_64 defconfig caught my attention with:
kernel/printk/printk_ringbuffer.c:885:3: warning:
Value stored to 'desc' is never read [clang-analyzer-deadcode.DeadStores]desc = to_desc(desc_ring, head_id);
^Commit b6cf8b3f3312 ("printk: add lockless ringbuffer") introduced
desc_reserve() with this unneeded dead-store assignment.As discussed with John Ogness privately, this is probably just some minor
left-over from previous iterations of the ringbuffer implementation. So,
simply remove this unneeded dead assignment to make clang-analyzer happy.As compilers will detect this unneeded assignment and optimize this anyway,
the resulting object code is identical before and after this change.No functional change. No change to object code.
Signed-off-by: Lukas Bulwahn
Reviewed-by: Sergey Senozhatsky
Reviewed-by: John Ogness
Reviewed-by: Nathan Chancellor
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20201106034005.18822-1-lukas.bulwahn@gmail.com
31 Oct, 2020
1 commit
-
There is a regular need in the kernel to provide a way to declare having a
dynamically sized set of trailing elements in a structure. Kernel code should
always use “flexible array members”[1] for these cases. The older style of
one-element or zero-length arrays should no longer be used[2].[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.9/process/deprecated.html#zero-length-and-one-element-arraysSigned-off-by: Gustavo A. R. Silva
17 Oct, 2020
1 commit
-
Pull printk fix from Petr Mladek:
"Prevent overflow in the new lockless ringbuffer"* tag 'printk-for-5.10-fixup' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
printk: ringbuffer: Wrong data pointer when appending small string
16 Oct, 2020
1 commit
-
Pull trivial updates from Jiri Kosina:
"The latest advances in computer science from the trivial queue"* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial:
xtensa: fix Kconfig typo
spelling.txt: Remove some duplicate entries
mtd: rawnand: oxnas: cleanup/simplify code
selftests: vm: add fragment CONFIG_GUP_BENCHMARK
perf: Fix opt help text for --no-bpf-event
HID: logitech-dj: Fix spelling in comment
bootconfig: Fix kernel message mentioning CONFIG_BOOT_CONFIG
MAINTAINERS: rectify MMP SUPPORT after moving cputype.h
scif: Fix spelling of EACCES
printk: fix global comment
lib/bitmap.c: fix spello
fs: Fix missing 'bit' in comment
15 Oct, 2020
1 commit
-
data_realloc() returns wrong data pointer when the block is wrapped and
the size is not increased. It might happen when pr_cont() wants to
add only few characters and there is already a space for them because
of alignment.It might cause writing outsite the buffer. It has been detected by LTP
tests with KASAN enabled:[ 221.921944] oom-kill:constraint=CONSTRAINT_MEMCG,nodemask=(null),cpuset=c,mems_allowed=0,oom_memcg=/0,task_memcg=in
[ 221.922108] ==================================================================
[ 221.922111] BUG: KASAN: global-out-of-bounds in vprintk_store+0x362/0x3d0
[ 221.922112] Write of size 2 at addr ffffffffba51dbcd by task
memcg_test_1/11282
[ 221.922113]
[ 221.922114] CPU: 1 PID: 11282 Comm: memcg_test_1 Not tainted
5.9.0-next-20201013 #1
[ 221.922116] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS
2.0b 07/27/2017
[ 221.922116] Call Trace:
[ 221.922117] dump_stack+0xa4/0xd9
[ 221.922118] print_address_description.constprop.0+0x21/0x210
[ 221.922119] ? _raw_write_lock_bh+0xe0/0xe0
[ 221.922120] ? vprintk_store+0x362/0x3d0
[ 221.922121] kasan_report.cold+0x37/0x7c
[ 221.922122] ? vprintk_store+0x362/0x3d0
[ 221.922123] check_memory_region+0x18c/0x1f0
[ 221.922124] memcpy+0x3c/0x60
[ 221.922125] vprintk_store+0x362/0x3d0
[ 221.922125] ? __ia32_sys_syslog+0x50/0x50
[ 221.922126] ? _raw_spin_lock_irqsave+0x9b/0x100
[ 221.922127] ? _raw_spin_lock_irq+0xf0/0xf0
[ 221.922128] ? __kasan_check_write+0x14/0x20
[ 221.922129] vprintk_emit+0x8d/0x1f0
[ 221.922130] vprintk_default+0x1d/0x20
[ 221.922131] vprintk_func+0x5a/0x100
[ 221.922132] printk+0xb2/0xe3
[ 221.922133] ? swsusp_write.cold+0x189/0x189
[ 221.922134] ? kernfs_vfs_xattr_set+0x60/0x60
[ 221.922134] ? _raw_write_lock_bh+0xe0/0xe0
[ 221.922135] ? trace_hardirqs_on+0x38/0x100
[ 221.922136] pr_cont_kernfs_path.cold+0x49/0x4b
[ 221.922137] mem_cgroup_print_oom_context.cold+0x74/0xc3
[ 221.922138] dump_header+0x340/0x3bf
[ 221.922139] oom_kill_process.cold+0xb/0x10
[ 221.922140] out_of_memory+0x1e9/0x860
[ 221.922141] ? oom_killer_disable+0x210/0x210
[ 221.922142] mem_cgroup_out_of_memory+0x198/0x1c0
[ 221.922143] ? mem_cgroup_count_precharge_pte_range+0x250/0x250
[ 221.922144] try_charge+0xa9b/0xc50
[ 221.922145] ? arch_stack_walk+0x9e/0xf0
[ 221.922146] ? memory_high_write+0x230/0x230
[ 221.922146] ? avc_has_extended_perms+0x830/0x830
[ 221.922147] ? stack_trace_save+0x94/0xc0
[ 221.922148] ? stack_trace_consume_entry+0x90/0x90
[ 221.922149] __memcg_kmem_charge+0x73/0x120
[ 221.922150] ? cred_has_capability+0x10f/0x200
[ 221.922151] ? mem_cgroup_can_attach+0x260/0x260
[ 221.922152] ? selinux_sb_eat_lsm_opts+0x2f0/0x2f0
[ 221.922153] ? obj_cgroup_charge+0x16b/0x220
[ 221.922154] ? kmem_cache_alloc+0x78/0x4c0
[ 221.922155] obj_cgroup_charge+0x122/0x220
[ 221.922156] ? vm_area_alloc+0x20/0x90
[ 221.922156] kmem_cache_alloc+0x78/0x4c0
[ 221.922157] vm_area_alloc+0x20/0x90
[ 221.922158] mmap_region+0x3ed/0x9a0
[ 221.922159] ? cap_mmap_addr+0x1d/0x80
[ 221.922160] do_mmap+0x3ee/0x720
[ 221.922161] vm_mmap_pgoff+0x16a/0x1c0
[ 221.922162] ? randomize_stack_top+0x90/0x90
[ 221.922163] ? copy_page_range+0x1980/0x1980
[ 221.922163] ksys_mmap_pgoff+0xab/0x350
[ 221.922164] ? find_mergeable_anon_vma+0x110/0x110
[ 221.922165] ? __audit_syscall_entry+0x1a6/0x1e0
[ 221.922166] __x64_sys_mmap+0x8d/0xb0
[ 221.922167] do_syscall_64+0x38/0x50
[ 221.922168] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 221.922169] RIP: 0033:0x7fe8f5e75103
[ 221.922172] Code: 54 41 89 d4 55 48 89 fd 53 4c 89 cb 48 85 ff 74
56 49 89 d9 45 89 f8 45 89 f2 44 89 e2 4c 89 ee 48 89 ef b8 09 00 00
00 0f 05 3d 00 f0 ff ff 77 7d 5b 5d 41 5c 41 5d 41 5e 41 5f c3 66
2e 0f
[ 221.922173] RSP: 002b:00007ffd38c90198 EFLAGS: 00000246 ORIG_RAX:
0000000000000009
[ 221.922175] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fe8f5e75103
[ 221.922176] RDX: 0000000000000003 RSI: 0000000000001000 RDI: 0000000000000000
[ 221.922178] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[ 221.922179] R10: 0000000000002022 R11: 0000000000000246 R12: 0000000000000003
[ 221.922180] R13: 0000000000001000 R14: 0000000000002022 R15: 0000000000000000
[ 221.922181]
[ 213O[ 221.922182] The buggy address belongs to the variable:
[ 221.922183] clear_seq+0x2d/0x40
[ 221.922183]
[ 221.922184] Memory state around the buggy address:
[ 221.922185] ffffffffba51da80: 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00
[ 221.922187] ffffffffba51db00: 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00
[ 221.922188] >ffffffffba51db80: f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9
00 f9 f9 f9
[ 221.922189] ^
[ 221.922190] ffffffffba51dc00: f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9
00 f9 f9 f9
[ 221.922191] ffffffffba51dc80: f9 f9 f9 f9 01 f9 f9 f9 f9 f9 f9 f9
00 f9 f9 f9
[ 221.922193] ==================================================================
[ 221.922194] Disabling lock debugging due to kernel taint
[ 221.922196] ,task=memcg_test_1,pid=11280,uid=0
[ 221.922205] Memory cgroup out of memory: Killed process 11280Link: https://lore.kernel.org/r/CA+G9fYt46oC7-BKryNDaaXPJ9GztvS2cs_7GjYRjanRi4+ryCQ@mail.gmail.com
Fixes: 4cfc7258f876a7feba673ac ("printk: ringbuffer: add finalization/extension support")
Reported-by: Naresh Kamboju
Reviewed-by: John Ogness
Acked-by: Sergey Senozhatsky
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20201014175051.GC13775@alley
12 Oct, 2020
1 commit
05 Oct, 2020
1 commit
-
Replace /* FALL THRU */ comment with the new pseudo-keyword macro
fallthrough[1].[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through
Signed-off-by: Gustavo A. R. Silva
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20201002224627.GA30475@embeddedor
30 Sep, 2020
2 commits
-
@setup_text_buf only copies the original text messages (without any
prefix or extended text). It only needs to be LOG_LINE_MAX in size.Signed-off-by: John Ogness
Reviewed-by: Petr Mladek
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20200930090134.8723-3-john.ogness@linutronix.de -
If a reader provides a buffer that is smaller than the message text,
the @text_len field of @info will have a value larger than the buffer
size. If readers blindly read @text_len bytes of data without
checking the size, they will read beyond their buffer.Add this check to record_print_text() to properly recognize when such
truncation has occurred.Add a maximum size argument to the ringbuffer function to extend
records so that records can not be created that are larger than the
buffer size of readers.When extending records (LOG_CONT), do not extend records beyond
LOG_LINE_MAX since that is the maximum size available in the buffers
used by consoles and syslog.Fixes: f5f022e53b87 ("printk: reimplement log_cont using record extension")
Reported-by: Marek Szyprowski
Signed-off-by: John Ogness
Reviewed-by: Petr Mladek
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20200930090134.8723-2-john.ogness@linutronix.de
22 Sep, 2020
3 commits
-
Since there is no code that will ever store anything into the dict
ring, remove it. If any future dictionary properties are to be
added, these should be added to the struct printk_info.Signed-off-by: John Ogness
Reviewed-by: Petr Mladek
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20200918223421.21621-4-john.ogness@linutronix.de -
Dictionaries are only used for SUBSYSTEM and DEVICE properties. The
current implementation stores the property names each time they are
used. This requires more space than otherwise necessary. Also,
because the dictionary entries are currently considered optional,
it cannot be relied upon that they are always available, even if the
writer wanted to store them. These issues will increase should new
dictionary properties be introduced.Rather than storing the subsystem and device properties in the
dict ring, introduce a struct dev_printk_info with separate fields
to store only the property values. Embed this struct within the
struct printk_info to provide guaranteed availability.Signed-off-by: John Ogness
Reviewed-by: Petr Mladek
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/87mu1jl6ne.fsf@jogness.linutronix.de -
The majority of the size of a descriptor is taken up by meta data,
which is often not of interest to the ringbuffer (for example,
when performing state checks). Since descriptors are often
temporarily stored on the stack, keeping their size minimal will
help reduce stack pressure.Rather than embedding the printk_info into the descriptor, create
a separate printk_info array. The index of a descriptor in the
descriptor array corresponds to the printk_info with the same
index in the printk_info array. The rules for validity of a
printk_info match the existing rules for the data blocks: the
descriptor must be in a consistent state.Signed-off-by: John Ogness
Reviewed-by: Petr Mladek
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20200918223421.21621-2-john.ogness@linutronix.de
15 Sep, 2020
8 commits
-
Use the record extending feature of the ringbuffer to implement
continuous messages. This preserves the existing continuous message
behavior.Signed-off-by: John Ogness
Reviewed-by: Petr Mladek
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20200914123354.832-7-john.ogness@linutronix.de -
Add support for extending the newest data block. For this, introduce
a new finalization state (desc_finalized) denoting a committed
descriptor that cannot be extended.Until a record is finalized, a writer can reopen that record to
append new data. Reopening a record means transitioning from the
desc_committed state back to the desc_reserved state.A writer can explicitly finalize a record if there is no intention
of extending it. Also, records are automatically finalized when a
new record is reserved. This relieves writers of needing to
explicitly finalize while also making such records available to
readers sooner. (Readers can only traverse finalized records.)Four new memory barrier pairs are introduced. Two of them are
insignificant additions (data_realloc:A/desc_read:D and
data_realloc:A/data_push_tail:B) because they are alternate path
memory barriers that exactly match the purpose, pairing, and
context of the two existing memory barrier pairs they provide an
alternate path for. The other two new memory barrier pairs are
significant additions:desc_reopen_last:A / _prb_commit:B - When reopening a descriptor,
ensure the state transitions back to desc_reserved before
fully trusting the descriptor data._prb_commit:B / desc_reserve:D - When committing a descriptor,
ensure the state transitions to desc_committed before checking
the head ID to see if the descriptor needs to be finalized.Signed-off-by: John Ogness
Reviewed-by: Petr Mladek
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20200914123354.832-6-john.ogness@linutronix.de -
Rather than deriving the state by evaluating bits within the flags
area of the state variable, assign the states explicit values and
set those values in the flags area. Introduce macros to make it
simple to read and write state values for the state variable.Although the functionality is preserved, the binary representation
for the states is changed.Signed-off-by: John Ogness
Reviewed-by: Petr Mladek
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20200914123354.832-5-john.ogness@linutronix.de -
prb_reserve() will set some meta data values and leave others
uninitialized (or rather, containing the values of the previous
wrap). Simplify the API by always clearing out all the fields.
Only the sequence number is filled in. The caller is now
responsible for filling in the rest of the meta data fields.
In particular, for correctly filling in text and dict lengths.Signed-off-by: John Ogness
Reviewed-by: Petr Mladek
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20200914123354.832-4-john.ogness@linutronix.de -
Rather than continually needing to explicitly check @begin and @next
to identify a dataless block, introduce and use a BLK_DATALESS()
macro.Signed-off-by: John Ogness
Reviewed-by: Petr Mladek
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20200914123354.832-3-john.ogness@linutronix.de -
Move the internal get_data() function as-is above prb_reserve() so
that a later change can make use of the static function.Signed-off-by: John Ogness
Reviewed-by: Petr Mladek
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20200914123354.832-2-john.ogness@linutronix.de -
@state_var is copied as part of the descriptor copying via
memcpy(). This is not allowed because @state_var is an atomic type,
which in some implementations may contain a spinlock.Avoid using memcpy() with @state_var by explicitly copying the other
fields of the descriptor. @state_var is set using atomic set
operator before returning.Fixes: b6cf8b3f3312 ("printk: add lockless ringbuffer")
Signed-off-by: John Ogness
Reviewed-by: Petr Mladek
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20200914094803.27365-2-john.ogness@linutronix.de -
It is expected that desc_read() will always set at least the
@state_var field. However, if the descriptor is in an inconsistent
state, no fields are set.Also, the second load of @state_var is not stored in @desc_out and
so might not match the state value that is returned.Always set the last loaded @state_var into @desc_out, regardless of
the descriptor consistency.Fixes: b6cf8b3f3312 ("printk: add lockless ringbuffer")
Signed-off-by: John Ogness
Reviewed-by: Petr Mladek
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20200914094803.27365-1-john.ogness@linutronix.de
08 Sep, 2020
1 commit
-
With commit 896fbe20b4e2333fb55 ("printk: use the lockless ringbuffer"),
printk() started silently dropping messages without text because such
records are not supported by the new printk ringbuffer.Add support for such records.
Currently dataless records are denoted by INVALID_LPOS in order
to recognize failed prb_reserve() calls. Change the ringbuffer
to instead use two different identifiers (FAILED_LPOS and
NO_LPOS) to distinguish between failed prb_reserve() records and
successful dataless records, respectively.Fixes: 896fbe20b4e2333fb55 ("printk: use the lockless ringbuffer")
Fixes: https://lkml.kernel.org/r/20200718121053.GA691245@elver.google.com
Reported-by: Marco Elver
Signed-off-by: John Ogness
Cc: Petr Mladek
Cc: Steven Rostedt
Cc: Marco Elver
Signed-off-by: Sergey Senozhatsky
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20200721132528.9661-1-john.ogness@linutronix.de
01 Sep, 2020
1 commit
-
Sync with Linus' branch in order to be able to apply fixups
of more recent patches.
10 Aug, 2020
1 commit
-
Drop repeated words "the" in kernel/printk/.
Signed-off-by: Randy Dunlap
Cc: Sergey Senozhatsky
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20200807033227.8349-1-rdunlap@infradead.org
05 Aug, 2020
1 commit
-
Pull printk updates from Petr Mladek:
- Herbert Xu made printk header file self-contained.
- Andy Shevchenko and Sergey Senozhatsky cleaned up console->setup()
error handling.- Andy Shevchenko did some cleanups (e.g. sparse warning) in vsprintf
code.- Minor documentation updates.
* tag 'printk-for-5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
lib/vsprintf: Force type of flags value for gfp_t
lib/vsprintf: Replace custom spec to print decimals with generic one
lib/vsprintf: Replace hidden BUILD_BUG_ON() with static_assert()
printk: Make linux/printk.h self-contained
doc:kmsg: explicitly state the return value in case of SEEK_CUR
Replace HTTP links with HTTPS ones: vsprintf
hvc: unify console setup naming
console: Fix trivia typo 'change' -> 'chance'
console: Propagate error code from console ->setup()
tty: hvc: Return proper error code from console ->setup() hook
serial: sunzilog: Return proper error code from console ->setup() hook
serial: sunsab: Return proper error code from console ->setup() hook
mips: Return proper error code from console ->setup() hook
04 Aug, 2020
1 commit
13 Jul, 2020
1 commit
-
The commit 625d3449788f ("Revert "kernel/printk: add kmsg SEEK_CUR
handling"") reverted a change done to the return value in case a SEEK_CUR
operation was performed for kmsg buffer based on the fact that different
userspace apps were handling the new return value (-ESPIPE) in different
ways, breaking them.At the same time -ESPIPE was the wrong decision because kmsg /does support/
seek() but doesn't follow the "normal" behavior userspace is used to.
Because of that and also considering the time -EINVAL has been used, it was
decided to keep this way to avoid more userspace breakage.This patch adds an official statement to the kmsg documentation pointing to
the current return value for SEEK_CUR, -EINVAL, thus userspace libraries
and apps can refer to it for a definitive guide on what to expect.Signed-off-by: Bruno Meneguele
Reviewed-by: Sergey Senozhatsky
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20200710174423.10480-1-bmeneg@redhat.com
10 Jul, 2020
3 commits
-
Replace the existing ringbuffer usage and implementation with
lockless ringbuffer usage. Even though the new ringbuffer does not
require locking, all existing locking is left in place. Therefore,
this change is purely replacing the underlining ringbuffer.Changes that exist due to the ringbuffer replacement:
- The VMCOREINFO has been updated for the new structures.
- Dictionary data is now stored in a separate data buffer from the
human-readable messages. The dictionary data buffer is set to the
same size as the message buffer. Therefore, the total required
memory for both dictionary and message data is
2 * (2 ^ CONFIG_LOG_BUF_SHIFT) for the initial static buffers and
2 * log_buf_len (the kernel parameter) for the dynamic buffers.- Record meta-data is now stored in a separate array of descriptors.
This is an additional 72 * (2 ^ (CONFIG_LOG_BUF_SHIFT - 5)) bytes
for the static array and 72 * (log_buf_len >> 5) bytes for the
dynamic array.Signed-off-by: John Ogness
Reviewed-by: Petr Mladek
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20200709132344.760-5-john.ogness@linutronix.de -
This reverts commit 3ac37a93fa9217e576bebfd4ba3e80edaaeb2289.
This optimization will not apply once the transition to a lockless
printk is complete. Rather than porting this optimization through
the transition only to remove it anyway, just revert it now to
simplify the transition.Signed-off-by: John Ogness
Reviewed-by: Petr Mladek
Acked-by: Sergey Senozhatsky
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20200709132344.760-4-john.ogness@linutronix.de -
Introduce a multi-reader multi-writer lockless ringbuffer for storing
the kernel log messages. Readers and writers may use their API from
any context (including scheduler and NMI). This ringbuffer will make
it possible to decouple printk() callers from any context, locking,
or console constraints. It also makes it possible for readers to have
full access to the ringbuffer contents at any time and context (for
example from any panic situation).The printk_ringbuffer is made up of 3 internal ringbuffers:
desc_ring:
A ring of descriptors. A descriptor contains all record meta data
(sequence number, timestamp, loglevel, etc.) as well as internal state
information about the record and logical positions specifying where in
the other ringbuffers the text and dictionary strings are located.text_data_ring:
A ring of data blocks. A data block consists of an unsigned long
integer (ID) that maps to a desc_ring index followed by the text
string of the record.dict_data_ring:
A ring of data blocks. A data block consists of an unsigned long
integer (ID) that maps to a desc_ring index followed by the dictionary
string of the record.The internal state information of a descriptor is the key element to
allow readers and writers to locklessly synchronize access to the data.Co-developed-by: Petr Mladek
Signed-off-by: John Ogness
Reviewed-by: Petr Mladek
Reviewed-by: Paul E. McKenney
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20200709132344.760-3-john.ogness@linutronix.de
25 Jun, 2020
2 commits
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I bet the word 'chance' has to be used in 'had a chance to be called',
but, alas, I'm not native speaker...Signed-off-by: Andy Shevchenko
Reviewed-by: Petr Mladek
Acked-by: Benjamin Herrenschmidt
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20200618164751.56828-7-andriy.shevchenko@linux.intel.com -
Since console ->setup() hook returns meaningful error codes,
propagate it to the caller of try_enable_new_console().Signed-off-by: Andy Shevchenko
Reviewed-by: Petr Mladek
Acked-by: Benjamin Herrenschmidt
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20200618164751.56828-6-andriy.shevchenko@linux.intel.com
22 Jun, 2020
1 commit
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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/kmsgThis 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
Cc: Sergey Senozhatsky
Cc: Steven Rostedt
Cc: David Laight
Cc: Sergey Senozhatsky
Cc: Petr Mladek
Signed-off-by: Jason A. Donenfeld
Signed-off-by: Linus Torvalds
13 Jun, 2020
1 commit
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Pull printk fix from Petr Mladek:
"One more printk change for 5.8: make sure that messages printed from
KDB context are redirected to KDB console handlers. It did not work
when KDB interrupted NMI or printk_safe contexts.Arm people started hitting this problem more often recently. I forgot
to add the fix into the previous pull request by mistake"* tag 'printk-for-5.8-kdb-nmi' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
printk/kdb: Redirect printk messages into kdb in any context
11 Jun, 2020
1 commit
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kdb has to get messages on consoles even when the system is stopped.
It uses kdb_printf() internally and calls console drivers on its own.It uses a hack to reuse an existing code. It sets "kdb_trap_printk"
global variable to redirect even the normal printk() into the
kdb_printf() variant.The variable "kdb_trap_printk" is checked in printk_default() and
it is ignored when printk is redirected to printk_safe in NMI context.
Solve this by moving the check into printk_func().It is obvious that it is not fully safe. But it does not make things
worse. The console drivers are already called in this context by
db_printf() direct calls.Reported-by: Sumit Garg
Tested-by: Sumit Garg
Reviewed-by: Daniel Thompson
Acked-by: Sergey Senozhatsky
Signed-off-by: Petr Mladek
Link: https://lore.kernel.org/r/20200520102233.GC3464@linux-b0ei
04 Jun, 2020
1 commit
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Pull networking updates from David Miller:
1) Allow setting bluetooth L2CAP modes via socket option, from Luiz
Augusto von Dentz.2) Add GSO partial support to igc, from Sasha Neftin.
3) Several cleanups and improvements to r8169 from Heiner Kallweit.
4) Add IF_OPER_TESTING link state and use it when ethtool triggers a
device self-test. From Andrew Lunn.5) Start moving away from custom driver versions, use the globally
defined kernel version instead, from Leon Romanovsky.6) Support GRO vis gro_cells in DSA layer, from Alexander Lobakin.
7) Allow hard IRQ deferral during NAPI, from Eric Dumazet.
8) Add sriov and vf support to hinic, from Luo bin.
9) Support Media Redundancy Protocol (MRP) in the bridging code, from
Horatiu Vultur.10) Support netmap in the nft_nat code, from Pablo Neira Ayuso.
11) Allow UDPv6 encapsulation of ESP in the ipsec code, from Sabrina
Dubroca. Also add ipv6 support for espintcp.12) Lots of ReST conversions of the networking documentation, from Mauro
Carvalho Chehab.13) Support configuration of ethtool rxnfc flows in bcmgenet driver,
from Doug Berger.14) Allow to dump cgroup id and filter by it in inet_diag code, from
Dmitry Yakunin.15) Add infrastructure to export netlink attribute policies to
userspace, from Johannes Berg.16) Several optimizations to sch_fq scheduler, from Eric Dumazet.
17) Fallback to the default qdisc if qdisc init fails because otherwise
a packet scheduler init failure will make a device inoperative. From
Jesper Dangaard Brouer.18) Several RISCV bpf jit optimizations, from Luke Nelson.
19) Correct the return type of the ->ndo_start_xmit() method in several
drivers, it's netdev_tx_t but many drivers were using
'int'. From Yunjian Wang.20) Add an ethtool interface for PHY master/slave config, from Oleksij
Rempel.21) Add BPF iterators, from Yonghang Song.
22) Add cable test infrastructure, including ethool interfaces, from
Andrew Lunn. Marvell PHY driver is the first to support this
facility.23) Remove zero-length arrays all over, from Gustavo A. R. Silva.
24) Calculate and maintain an explicit frame size in XDP, from Jesper
Dangaard Brouer.25) Add CAP_BPF, from Alexei Starovoitov.
26) Support terse dumps in the packet scheduler, from Vlad Buslov.
27) Support XDP_TX bulking in dpaa2 driver, from Ioana Ciornei.
28) Add devm_register_netdev(), from Bartosz Golaszewski.
29) Minimize qdisc resets, from Cong Wang.
30) Get rid of kernel_getsockopt and kernel_setsockopt in order to
eliminate set_fs/get_fs calls. From Christoph Hellwig.* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2517 commits)
selftests: net: ip_defrag: ignore EPERM
net_failover: fixed rollback in net_failover_open()
Revert "tipc: Fix potential tipc_aead refcnt leak in tipc_crypto_rcv"
Revert "tipc: Fix potential tipc_node refcnt leak in tipc_rcv"
vmxnet3: allow rx flow hash ops only when rss is enabled
hinic: add set_channels ethtool_ops support
selftests/bpf: Add a default $(CXX) value
tools/bpf: Don't use $(COMPILE.c)
bpf, selftests: Use bpf_probe_read_kernel
s390/bpf: Use bcr 0,%0 as tail call nop filler
s390/bpf: Maintain 8-byte stack alignment
selftests/bpf: Fix verifier test
selftests/bpf: Fix sample_cnt shared between two threads
bpf, selftests: Adapt cls_redirect to call csum_level helper
bpf: Add csum_level helper for fixing up csum levels
bpf: Fix up bpf_skb_adjust_room helper's skb csum setting
sfc: add missing annotation for efx_ef10_try_update_nic_stats_vf()
crypto/chtls: IPv6 support for inline TLS
Crypto/chcr: Fixes a coccinile check error
Crypto/chcr: Fixes compilations warnings
...
02 Jun, 2020
2 commits
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Pull RCU updates from Ingo Molnar:
"The RCU updates for this cycle were:- RCU-tasks update, including addition of RCU Tasks Trace for BPF use
and TASKS_RUDE_RCU- kfree_rcu() updates.
- Remove scheduler locking restriction
- RCU CPU stall warning updates.
- Torture-test updates.
- Miscellaneous fixes and other updates"
* tag 'core-rcu-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (103 commits)
rcu: Allow for smp_call_function() running callbacks from idle
rcu: Provide rcu_irq_exit_check_preempt()
rcu: Abstract out rcu_irq_enter_check_tick() from rcu_nmi_enter()
rcu: Provide __rcu_is_watching()
rcu: Provide rcu_irq_exit_preempt()
rcu: Make RCU IRQ enter/exit functions rely on in_nmi()
rcu/tree: Mark the idle relevant functions noinstr
x86: Replace ist_enter() with nmi_enter()
x86/mce: Send #MC singal from task work
x86/entry: Get rid of ist_begin/end_non_atomic()
sched,rcu,tracing: Avoid tracing before in_nmi() is correct
sh/ftrace: Move arch_ftrace_nmi_{enter,exit} into nmi exception
lockdep: Always inline lockdep_{off,on}()
hardirq/nmi: Allow nested nmi_enter()
arm64: Prepare arch_nmi_enter() for recursion
printk: Disallow instrumenting print_nmi_enter()
printk: Prepare for nested printk_nmi_enter()
rcutorture: Convert ULONG_CMP_LT() to time_before()
torture: Add a --kasan argument
torture: Save a few lines by using config_override_param initially
... -
Pull printk updates from Petr Mladek:
- Benjamin Herrenschmidt solved a problem with non-matched console
aliases by first checking consoles defined on the command line. It is
a more conservative approach than the previous attempts.- Benjamin also made sure that the console accessible via /dev/console
always has CON_CONSDEV flag.- Andy Shevchenko added the %ptT modifier for printing struct time64_t.
It extends the existing %ptR handling for struct rtc_time.- Bruno Meneguele fixed /dev/kmsg error value returned by unsupported
SEEK_CUR.- Tetsuo Handa removed unused pr_cont_once().
... and a few small fixes.
* tag 'printk-for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
printk: Remove pr_cont_once()
printk: handle blank console arguments passed in.
kernel/printk: add kmsg SEEK_CUR handling
printk: Fix a typo in comment "interator"->"iterator"
usb: pulse8-cec: Switch to use %ptT
ARM: bcm2835: Switch to use %ptT
lib/vsprintf: Print time64_t in human readable format
lib/vsprintf: update comment about simple_strto() functions
printk: Correctly set CON_CONSDEV even when preferred console was not registered
printk: Fix preferred console selection with multiple matches
printk: Move console matching logic into a separate function
printk: Convert a use of sprintf to snprintf in console_unlock