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Damien Le Moal 0eced76360 scsi: mpt3sas: Fix unlock imbalance
[ Upstream commit cb551b8dc0 ]

In BRM_status_show(), if the condition "!ioc->is_warpdrive" tested on entry
to the function is true, a "goto out" is called. This results in unlocking
ioc->pci_access_mutex without this mutex lock being taken.  This generates
the following splat:

[ 1148.539883] mpt3sas_cm2: BRM_status_show: BRM attribute is only for warpdrive
[ 1148.547184]
[ 1148.548708] =====================================
[ 1148.553501] WARNING: bad unlock balance detected!
[ 1148.558277] 5.8.0-rc3+ #827 Not tainted
[ 1148.562183] -------------------------------------
[ 1148.566959] cat/5008 is trying to release lock (&ioc->pci_access_mutex) at:
[ 1148.574035] [<ffffffffc070b7a3>] BRM_status_show+0xd3/0x100 [mpt3sas]
[ 1148.580574] but there are no more locks to release!
[ 1148.585524]
[ 1148.585524] other info that might help us debug this:
[ 1148.599624] 3 locks held by cat/5008:
[ 1148.607085]  #0: ffff92aea3e392c0 (&p->lock){+.+.}-{3:3}, at: seq_read+0x34/0x480
[ 1148.618509]  #1: ffff922ef14c4888 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x2a/0xb0
[ 1148.630729]  #2: ffff92aedb5d7310 (kn->active#224){.+.+}-{0:0}, at: kernfs_seq_start+0x32/0xb0
[ 1148.643347]
[ 1148.643347] stack backtrace:
[ 1148.655259] CPU: 73 PID: 5008 Comm: cat Not tainted 5.8.0-rc3+ #827
[ 1148.665309] Hardware name: HGST H4060-S/S2600STB, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019
[ 1148.678394] Call Trace:
[ 1148.684750]  dump_stack+0x78/0xa0
[ 1148.691802]  lock_release.cold+0x45/0x4a
[ 1148.699451]  __mutex_unlock_slowpath+0x35/0x270
[ 1148.707675]  BRM_status_show+0xd3/0x100 [mpt3sas]
[ 1148.716092]  dev_attr_show+0x19/0x40
[ 1148.723664]  sysfs_kf_seq_show+0x87/0x100
[ 1148.731193]  seq_read+0xbc/0x480
[ 1148.737882]  vfs_read+0xa0/0x160
[ 1148.744514]  ksys_read+0x58/0xd0
[ 1148.751129]  do_syscall_64+0x4c/0xa0
[ 1148.757941]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 1148.766240] RIP: 0033:0x7f1230566542
[ 1148.772957] Code: Bad RIP value.
[ 1148.779206] RSP: 002b:00007ffeac1bcac8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
[ 1148.790063] RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007f1230566542
[ 1148.800284] RDX: 0000000000020000 RSI: 00007f1223460000 RDI: 0000000000000003
[ 1148.810474] RBP: 00007f1223460000 R08: 00007f122345f010 R09: 0000000000000000
[ 1148.820641] R10: 0000000000000022 R11: 0000000000000246 R12: 0000000000000000
[ 1148.830728] R13: 0000000000000003 R14: 0000000000020000 R15: 0000000000020000

Fix this by returning immediately instead of jumping to the out label.

Link: https://lore.kernel.org/r/20200701085254.51740-1-damien.lemoal@wdc.com
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Acked-by: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-07-29 10:18:27 +02:00
Documentation doc: dt: bindings: usb: dwc3: Update entries for disabling SS instances in park mode 2020-07-22 09:32:59 +02:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch xtensa: update *pos in cpuinfo_op.next 2020-07-29 10:18:26 +02:00
block block: fix get_max_segment_size() overflow on 32bit arch 2020-07-22 09:33:17 +02:00
certs PKCS#7: Refactor verify_pkcs7_signature() 2019-08-05 18:40:18 -04:00
crypto keys: asymmetric: fix error return code in software_key_query() 2020-07-22 09:33:04 +02:00
drivers scsi: mpt3sas: Fix unlock imbalance 2020-07-29 10:18:27 +02:00
fs fuse: Fix parameter for FS_IOC_{GET,SET}FLAGS 2020-07-22 09:33:12 +02:00
include rxrpc: Fix trace string 2020-07-22 09:33:17 +02:00
init x86: Fix early boot crash on gcc-10, third try 2020-05-20 08:20:34 +02:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel genirq/affinity: Handle affinity setting on inactive interrupts correctly 2020-07-22 09:33:16 +02:00
lib test_objagg: Fix potential memory leak in error handling 2020-06-30 15:37:04 -04:00
mm mm, compaction: make capture control handling safe wrt interrupts 2020-07-09 09:37:57 +02:00
net mac80211: allow rx of mesh eapol frames with default rx key 2020-07-29 10:18:26 +02:00
samples samples/vfs: avoid warning in statx override 2020-07-09 09:37:54 +02:00
scripts recordmcount: support >64k sections 2020-06-30 15:37:05 -04:00
security apparmor: ensure that dfa state tables have entries 2020-07-22 09:33:05 +02:00
sound ALSA: hda/realtek - Enable Speaker for ASUS UX563 2020-07-22 09:33:09 +02:00
tools perf stat: Zero all the 'ena' and 'run' array slot stats for interval mode 2020-07-22 09:33:05 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: arm64: Save the host's PtrAuth keys in non-preemptible context 2020-06-17 16:40:38 +02:00
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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.