android_kernel_samsung_sm8650

Kernel for Galaxy S24, rebased on CLO sources (WIP)

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Petr Mladek d303de1fcf tracing: Initialize iter->seq after zeroing in tracing_read_pipe() A customer reported the following softlockup: [899688.160002] NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [test.sh:16464] [899688.160002] CPU: 0 PID: 16464 Comm: test.sh Not tainted 4.12.14-6.23-azure #1 SLE12-SP4 [899688.160002] RIP: 0010:up_write+0x1a/0x30 [899688.160002] Kernel panic - not syncing: softlockup: hung tasks [899688.160002] RIP: 0010:up_write+0x1a/0x30 [899688.160002] RSP: 0018:ffffa86784d4fde8 EFLAGS: 00000257 ORIG_RAX: ffffffffffffff12 [899688.160002] RAX: ffffffff970fea00 RBX: 0000000000000001 RCX: 0000000000000000 [899688.160002] RDX: ffffffff00000001 RSI: 0000000000000080 RDI: ffffffff970fea00 [899688.160002] RBP: ffffffffffffffff R08: ffffffffffffffff R09: 0000000000000000 [899688.160002] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8b59014720d8 [899688.160002] R13: ffff8b59014720c0 R14: ffff8b5901471090 R15: ffff8b5901470000 [899688.160002] tracing_read_pipe+0x336/0x3c0 [899688.160002] __vfs_read+0x26/0x140 [899688.160002] vfs_read+0x87/0x130 [899688.160002] SyS_read+0x42/0x90 [899688.160002] do_syscall_64+0x74/0x160 It caught the process in the middle of trace_access_unlock(). There is no loop. So, it must be looping in the caller tracing_read_pipe() via the "waitagain" label. Crashdump analyze uncovered that iter->seq was completely zeroed at this point, including iter->seq.seq.size. It means that print_trace_line() was never able to print anything and there was no forward progress. The culprit seems to be in the code: /* reset all but tr, trace, and overruns */ memset(&iter->seq, 0, sizeof(struct trace_iterator) - offsetof(struct trace_iterator, seq)); It was added by the commit `53d0aa7730` ("ftrace: add logic to record overruns"). It was v2.6.27-rc1. It was the time when iter->seq looked like: struct trace_seq { unsigned char buffer[PAGE_SIZE]; unsigned int len; }; There was no "size" variable and zeroing was perfectly fine. The solution is to reinitialize the structure after or without zeroing. Link: http://lkml.kernel.org/r/20191011142134.11997-1-pmladek@suse.com Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>		2019-10-12 20:49:34 -04:00
arch	ARM: SoC fixes	2019-10-05 17:18:43 -07:00
block	block: sed-opal: fix sparse warning: convert __be64 data	2019-10-03 14:21:32 -06:00
certs	PKCS#7: Refactor verify_pkcs7_signature()	2019-08-05 18:40:18 -04:00
crypto	Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security	2019-09-28 08:14:15 -07:00
Documentation	Kbuild fixes for v5.4	2019-10-05 12:56:59 -07:00
drivers	ARM: SoC fixes	2019-10-05 17:18:43 -07:00
fs	tracing: Do not create tracefs files if tracefs lockdown is in effect	2019-10-12 20:49:07 -04:00
include	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net	2019-10-05 08:50:15 -07:00
init	Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security	2019-09-28 08:14:15 -07:00
ipc	ipc/sem.c: convert to use built-in RCU list checking	2019-09-25 17:51:41 -07:00
kernel	tracing: Initialize iter->seq after zeroing in tracing_read_pipe()	2019-10-12 20:49:34 -04:00
lib	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net	2019-10-05 08:50:15 -07:00
LICENSES	LICENSES: Rename other to deprecated	2019-05-03 06:34:32 -06:00
mm	Merge branch 'hugepage-fallbacks' (hugepatch patches from David Rientjes)	2019-09-28 14:26:47 -07:00
net	nfc: fix memory leak in llcp_sock_bind()	2019-10-04 18:31:36 -07:00
samples	rpmsg updates for v5.4	2019-09-22 10:58:15 -07:00
scripts	recordmcount: Fix nop_mcount() function	2019-10-12 20:49:33 -04:00
security	integrity: remove pointless subdir-$(CONFIG_...)	2019-10-05 15:29:49 +09:00
sound	sound fixes for 5.4-rc1	2019-09-24 16:46:16 -07:00
tools	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net	2019-10-05 08:50:15 -07:00
usr	kbuild: update compile-test header list for v5.4-rc2	2019-10-05 15:29:49 +09:00
virt	KVM/arm fixes for 5.4, take #1	2019-10-03 12:08:50 +02:00
.clang-format	clang-format: Update with the latest for_each macro list	2019-08-31 10:00:51 +02:00
.cocciconfig
.get_maintainer.ignore	Opt out of scripts/get_maintainer.pl	2019-05-16 10:53:40 -07:00
.gitattributes
.gitignore	Modules updates for v5.4	2019-09-22 10:34:46 -07:00
.mailmap	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next	2019-09-18 12:34:53 -07:00
COPYING	COPYING: use the new text with points to the license files	2018-03-23 12:41:45 -06:00
CREDITS	CREDITS: Update email address	2019-09-13 17:21:38 +03:00
Kbuild	kbuild: do not descend to ./Kbuild when cleaning	2019-08-21 21:03:58 +09:00
Kconfig	docs: kbuild: convert docs to ReST and rename to *.rst	2019-06-14 14:21:21 -06:00
MAINTAINERS	kgdb patches for 5.4-rc2	2019-10-03 11:17:57 -07:00
Makefile	Linux 5.4-rc2	2019-10-06 14:27:30 -07:00
README	Drop all 00-INDEX files from Documentation/	2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.