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This affects at least versions 25 and 33, so assume all cards are broken
and just renegotiate by default.
Fixes: 10bc6a6042c9 ("r8169: fix autoneg issue on resume with RTL8168E")
Signed-off-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Caching ip_hdr(skb) before a call to pskb_may_pull() is buggy,
do not do it.
Fixes: 2efd4fca703a ("ip: in cmsg IP(V6)_ORIGDSTADDR call pskb_may_pull")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/saeed/linux
Saeed Mahameed says:
====================
Mellanox, mlx5 fixes 2018-10-01
This pull request includes some fixes to mlx5 driver,
Please pull and let me know if there's any problem.
For -stable v4.11:
"6e0a4a23c59a ('net/mlx5: E-Switch, Fix out of bound access when setting vport rate')"
For -stable v4.18:
"98d6627c372a ('net/mlx5e: Set vlan masks for all offloaded TC rules')"
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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Subash Abhinov Kasiviswanathan says:
====================
net: qualcomm: rmnet: Updates 2018-10-02
This series is a set of small fixes for rmnet driver
Patch 1 is a fix for a scenario reported by syzkaller
Patch 2 & 3 are fixes for incorrect allocation flags
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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The incoming skb needs to be reallocated in case the headroom
is not sufficient to adjust the ethernet header. This allocation
needs to be atomic otherwise it results in this splat
[<600601bb>] ___might_sleep+0x185/0x1a3
[<603f6314>] ? _raw_spin_unlock_irqrestore+0x0/0x27
[<60069bb0>] ? __wake_up_common_lock+0x95/0xd1
[<600602b0>] __might_sleep+0xd7/0xe2
[<60065598>] ? enqueue_task_fair+0x112/0x209
[<600eea13>] __kmalloc_track_caller+0x5d/0x124
[<600ee9b6>] ? __kmalloc_track_caller+0x0/0x124
[<602696d5>] __kmalloc_reserve.isra.34+0x30/0x7e
[<603f629b>] ? _raw_spin_lock_irqsave+0x0/0x3d
[<6026b744>] pskb_expand_head+0xbf/0x310
[<6025ca6a>] rmnet_rx_handler+0x7e/0x16b
[<6025c9ec>] ? rmnet_rx_handler+0x0/0x16b
[<6027ad0c>] __netif_receive_skb_core+0x301/0x96f
[<60033c17>] ? set_signals+0x0/0x40
[<6027bbcb>] __netif_receive_skb+0x24/0x8e
Fixes: 74692caf1b0b ("net: qualcomm: rmnet: Process packets over ethernet")
Signed-off-by: Sean Tranchetti <stranche@codeaurora.org>
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The incoming skb needs to be reallocated in case the headroom
is not sufficient to add the MAP header. This allocation needs to
be atomic otherwise it results in the following splat
[32805.801456] BUG: sleeping function called from invalid context
[32805.841141] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
[32805.904773] task: ffffffd7c5f62280 task.stack: ffffff80464a8000
[32805.910851] pc : ___might_sleep+0x180/0x188
[32805.915143] lr : ___might_sleep+0x180/0x188
[32806.131520] Call trace:
[32806.134041] ___might_sleep+0x180/0x188
[32806.137980] __might_sleep+0x50/0x84
[32806.141653] __kmalloc_track_caller+0x80/0x3bc
[32806.146215] __kmalloc_reserve+0x3c/0x88
[32806.150241] pskb_expand_head+0x74/0x288
[32806.154269] rmnet_egress_handler+0xb0/0x1d8
[32806.162239] rmnet_vnd_start_xmit+0xc8/0x13c
[32806.166627] dev_hard_start_xmit+0x148/0x280
[32806.181181] sch_direct_xmit+0xa4/0x198
[32806.185125] __qdisc_run+0x1f8/0x310
[32806.188803] net_tx_action+0x23c/0x26c
[32806.192655] __do_softirq+0x220/0x408
[32806.196420] do_softirq+0x4c/0x70
Fixes: ceed73a2cf4a ("drivers: net: ethernet: qualcomm: rmnet: Initial implementation")
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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RMNET RX handler was processing invalid packets that were
originally sent on the real device and were looped back via
dev_loopback_xmit(). This was detected using syzkaller.
Fixes: ceed73a2cf4a ("drivers: net: ethernet: qualcomm: rmnet: Initial implementation")
Signed-off-by: Sean Tranchetti <stranche@codeaurora.org>
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The AON_PM_L2 is normally used to trigger and identify the source of a
wake-up event. Since the RX_SYS clock is no longer turned off, we also
have an interrupt being sent to the SYSTEMPORT INTRL_2_0 controller, and
that interrupt remains active up until the magic packet detector is
disabled which happens much later during the driver resumption.
The race happens if we have a CPU that is entering the SYSTEMPORT
INTRL2_0 handler during resume, and another CPU has managed to clear the
wake-up interrupt during bcm_sysport_resume_from_wol(). In that case, we
have the first CPU stuck in the interrupt handler with an interrupt
cause that has been cleared under its feet, and so we keep returning
IRQ_NONE and we never make any progress.
This was not a problem before because we would always turn off the
RX_SYS clock during WoL, so the SYSTEMPORT INTRL2_0 would also be turned
off as well, thus not latching the interrupt.
The fix is to make sure we do not enable either the MPD or
BRCM_TAG_MATCH interrupts since those are redundant with what the
AON_PM_L2 interrupt controller already processes and they would cause
such a race to occur.
Fixes: bb9051a2b230 ("net: systemport: Add support for WAKE_FILTER")
Fixes: 83e82f4c706b ("net: systemport: add Wake-on-LAN support")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Fixes problem (discovered by Aurelien) introduced by recent commit:
commit b24df3e30cbf48255db866720fb71f14bf9d2f39
("cifs: update receive_encrypted_standard to handle compounded responses")
which broke the ability to respond to some lease breaks
(lease breaks being ignored is a problem since can block
server response for duration of the lease break timeout).
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
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For compounded PDUs we whould only wake the waiting thread for the
very last PDU of the compound.
We do this so that we are guaranteed that the demultiplex_thread will
not process or access any of those MIDs any more once the send/recv
thread starts processing.
Else there is a race where at the end of the send/recv processing we
will try to delete all the mids of the compound. If the multiplex
thread still has other mids to process at this point for this compound
this can lead to an oops.
Needed to fix recent commit:
commit 730928c8f4be88e9d6a027a16b1e8fa9c59fc077
("cifs: update smb2_queryfs() to use compounding")
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/kvalo/wireless-drivers
Kalle Valo says:
====================
wireless-drivers fixes for 4.19
First, and also hopefully the last, set of fixes for 4.19. All small
but still important fixes
mt76x0
* fix a bug when a virtual interface is removed multiple times
b43
* fix DMA error related regression with proprietary firmware
iwlwifi
* fix an oops which was a regression in v4.19-rc1
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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cifs_delete_mid() is called once we are finished handling a mid and we
expect no more work done on this mid.
Needed to fix recent commit:
commit 730928c8f4be88e9d6a027a16b1e8fa9c59fc077
("cifs: update smb2_queryfs() to use compounding")
Add a warning if someone tries to dequeue a mid that has already been
flagged to be deleted.
Also change list_del() to list_del_init() so that if we have similar bugs
resurface in the future we will not oops.
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
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When mounting a Windows share that is the root of a drive (eg. C$)
the server does not return . and .. directory entries. This results in
the smb2 code path erroneously skipping the 2 first entries.
Pseudo-code of the readdir() code path:
cifs_readdir(struct file, struct dir_context)
initiate_cifs_search <-- if no reponse cached yet
server->ops->query_dir_first
dir_emit_dots
dir_emit <-- adds "." and ".." if we're at pos=0
find_cifs_entry
initiate_cifs_search <-- if pos < start of current response
(restart search)
server->ops->query_dir_next <-- if pos > end of current response
(fetch next search res)
for(...) <-- loops over cur response entries
starting at pos
cifs_filldir <-- skip . and .., emit entry
cifs_fill_dirent
dir_emit
pos++
A) dir_emit_dots() always adds . & ..
and sets the current dir pos to 2 (0 and 1 are done).
Therefore we always want the index_to_find to be 2 regardless of if
the response has . and ..
B) smb1 code initializes index_of_last_entry with a +2 offset
in cifssmb.c CIFSFindFirst():
psrch_inf->index_of_last_entry = 2 /* skip . and .. */ +
psrch_inf->entries_in_buffer;
Later in find_cifs_entry() we want to find the next dir entry at pos=2
as a result of (A)
first_entry_in_buffer = cfile->srch_inf.index_of_last_entry -
cfile->srch_inf.entries_in_buffer;
This var is the dir pos that the first entry in the buffer will
have therefore it must be 2 in the first call.
If we don't offset index_of_last_entry by 2 (like in (B)),
first_entry_in_buffer=0 but we were instructed to get pos=2 so this
code in find_cifs_entry() skips the 2 first which is ok for non-root
shares, as it skips . and .. from the response but is not ok for root
shares where the 2 first are actual files
pos_in_buf = index_to_find - first_entry_in_buffer;
// pos_in_buf=2
// we skip 2 first response entries :(
for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) {
/* go entry by entry figuring out which is first */
cur_ent = nxt_dir_entry(cur_ent, end_of_smb,
cfile->srch_inf.info_level);
}
C) cifs_filldir() skips . and .. so we can safely ignore them for now.
Sample program:
int main(int argc, char **argv)
{
const char *path = argc >= 2 ? argv[1] : ".";
DIR *dh;
struct dirent *de;
printf("listing path <%s>\n", path);
dh = opendir(path);
if (!dh) {
printf("opendir error %d\n", errno);
return 1;
}
while (1) {
de = readdir(dh);
if (!de) {
if (errno) {
printf("readdir error %d\n", errno);
return 1;
}
printf("end of listing\n");
break;
}
printf("off=%lu <%s>\n", de->d_off, de->d_name);
}
return 0;
}
Before the fix with SMB1 on root shares:
<.> off=1
<..> off=2
<$Recycle.Bin> off=3
<bootmgr> off=4
and on non-root shares:
<.> off=1
<..> off=4 <-- after adding .., the offsets jumps to +2 because
<2536> off=5 we skipped . and .. from response buffer (C)
<411> off=6 but still incremented pos
<file> off=7
<fsx> off=8
Therefore the fix for smb2 is to mimic smb1 behaviour and offset the
index_of_last_entry by 2.
Test results comparing smb1 and smb2 before/after the fix on root
share, non-root shares and on large directories (ie. multi-response
dir listing):
PRE FIX
=======
pre-1-root VS pre-2-root:
ERR pre-2-root is missing [bootmgr, $Recycle.Bin]
pre-1-nonroot VS pre-2-nonroot:
OK~ same files, same order, different offsets
pre-1-nonroot-large VS pre-2-nonroot-large:
OK~ same files, same order, different offsets
POST FIX
========
post-1-root VS post-2-root:
OK same files, same order, same offsets
post-1-nonroot VS post-2-nonroot:
OK same files, same order, same offsets
post-1-nonroot-large VS post-2-nonroot-large:
OK same files, same order, same offsets
REGRESSION?
===========
pre-1-root VS post-1-root:
OK same files, same order, same offsets
pre-1-nonroot VS post-1-nonroot:
OK same files, same order, same offsets
BugLink: https://bugzilla.samba.org/show_bug.cgi?id=13107
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Paulo Alcantara <palcantara@suse.deR>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
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We have an impressive number of syzkaller bugs that are linked
to the fact that syzbot was able to create a networking device
with millions of TX (or RX) queues.
Let's limit the number of RX/TX queues to 4096, this really should
cover all known cases.
A separate patch will add various cond_resched() in the loops
handling sysfs entries at device creation and dismantle.
Tested:
lpaa6:~# ip link add gre-4097 numtxqueues 4097 numrxqueues 4097 type ip6gretap
RTNETLINK answers: Invalid argument
lpaa6:~# time ip link add gre-4096 numtxqueues 4096 numrxqueues 4096 type ip6gretap
real 0m0.180s
user 0m0.000s
sys 0m0.107s
Fixes: 76ff5cc91935 ("rtnl: allow to specify number of rx and tx queues on device creation")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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RX queue config for bonding master could be different from its slave
device(s). With the commit 6a9e461f6fe4 ("bonding: pass link-local
packets to bonding master also."), the packet is reinjected into stack
with skb->dev as bonding master. This potentially triggers the
message:
"bondX received packet on queue Y, but number of RX queues is Z"
whenever the queue that packet is received on is higher than the
numrxqueues on bonding master (Y > Z).
Fixes: 6a9e461f6fe4 ("bonding: pass link-local packets to bonding master also.")
Reported-by: John Sperbeck <jsperbeck@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Timer handlers do not imply rcu_read_lock(), so my recent fix
triggered a LOCKDEP warning when SYNACK is retransmit.
Lets add rcu_read_lock()/rcu_read_unlock() pairs around ireq->ireq_opt
usages instead of guessing what is done by callers, since it is
not worth the pain.
Get rid of ireq_opt_deref() helper since it hides the logic
without real benefit, since it is now a standard rcu_dereference().
Fixes: 1ad98e9d1bdf ("tcp/dccp: fix lockdep issue when SYN is backlogged")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This reverts commit 2d4dd0da45401c7ae7332b4d1eb7bbb1348edde9.
This broke earlycon on all Renesas ARM platforms using a SCIF port for the
serial console (R-Car, RZ/A1, RZ/G1, RZ/G2 SoCs), due to an incorrect value
of port->regshift.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Chris Brandt <chris.brandt@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This reverts commit 7acece71a517cad83a0842a94d94c13f271b680c.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Chris Brandt <chris.brandt@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This reverts commit d76c74387e1c978b6c5524a146ab0f3f72206f98.
While commit d76c74387e1c ("serial: 8250_dw: Fix runtime PM handling")
fixes runtime PM handling when using kgdb, it introduces a traceback for
everyone else.
BUG: sleeping function called from invalid context at
/mnt/host/source/src/third_party/kernel/next/drivers/base/power/runtime.c:1034
in_atomic(): 1, irqs_disabled(): 1, pid: 1, name: swapper/0
7 locks held by swapper/0/1:
#0: 000000005ec5bc72 (&dev->mutex){....}, at: __driver_attach+0xb5/0x12b
#1: 000000005d5fa9e5 (&dev->mutex){....}, at: __device_attach+0x3e/0x15b
#2: 0000000047e93286 (serial_mutex){+.+.}, at: serial8250_register_8250_port+0x51/0x8bb
#3: 000000003b328f07 (port_mutex){+.+.}, at: uart_add_one_port+0xab/0x8b0
#4: 00000000fa313d4d (&port->mutex){+.+.}, at: uart_add_one_port+0xcc/0x8b0
#5: 00000000090983ca (console_lock){+.+.}, at: vprintk_emit+0xdb/0x217
#6: 00000000c743e583 (console_owner){-...}, at: console_unlock+0x211/0x60f
irq event stamp: 735222
__down_trylock_console_sem+0x4a/0x84
console_unlock+0x338/0x60f
__do_softirq+0x4a4/0x50d
irq_exit+0x64/0xe2
CPU: 2 PID: 1 Comm: swapper/0 Not tainted 4.19.0-rc5 #6
Hardware name: Google Caroline/Caroline, BIOS Google_Caroline.7820.286.0 03/15/2017
Call Trace:
dump_stack+0x7d/0xbd
___might_sleep+0x238/0x259
__pm_runtime_resume+0x4e/0xa4
? serial8250_rpm_get+0x2e/0x44
serial8250_console_write+0x44/0x301
? lock_acquire+0x1b8/0x1fa
console_unlock+0x577/0x60f
vprintk_emit+0x1f0/0x217
printk+0x52/0x6e
register_console+0x43b/0x524
uart_add_one_port+0x672/0x8b0
? set_io_from_upio+0x150/0x162
serial8250_register_8250_port+0x825/0x8bb
dw8250_probe+0x80c/0x8b0
? dw8250_serial_inq+0x8e/0x8e
? dw8250_check_lcr+0x108/0x108
? dw8250_runtime_resume+0x5b/0x5b
? dw8250_serial_outq+0xa1/0xa1
? dw8250_remove+0x115/0x115
platform_drv_probe+0x76/0xc5
really_probe+0x1f1/0x3ee
? driver_allows_async_probing+0x5d/0x5d
driver_probe_device+0xd6/0x112
? driver_allows_async_probing+0x5d/0x5d
bus_for_each_drv+0xbe/0xe5
__device_attach+0xdd/0x15b
bus_probe_device+0x5a/0x10b
device_add+0x501/0x894
? _raw_write_unlock+0x27/0x3a
platform_device_add+0x224/0x2b7
mfd_add_device+0x718/0x75b
? __kmalloc+0x144/0x16a
? mfd_add_devices+0x38/0xdb
mfd_add_devices+0x9b/0xdb
intel_lpss_probe+0x7d4/0x8ee
intel_lpss_pci_probe+0xac/0xd4
pci_device_probe+0x101/0x18e
...
Revert the offending patch until a more comprehensive solution
is available.
Cc: Tony Lindgren <tony@atomide.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Phil Edworthy <phil.edworthy@renesas.com>
Fixes: d76c74387e1c ("serial: 8250_dw: Fix runtime PM handling")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Use memblock_end_of_DRAM which provides correct last low memory
PFN. Without that, DMA32 region becomes empty resulting in zero
pages being allocated for DMA32.
This patch is based on earlier patch from palmer which never
merged into 4.19. I just edited the commit text to make more
sense.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
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The recent rework of the TSC calibration code introduced a regression on UV
systems as it added a call to tsc_early_init() which initializes the TSC
ADJUST values before acpi_boot_table_init(). In the case of UV systems,
that is a necessary step that calls uv_system_init(). This informs
tsc_sanitize_first_cpu() that the kernel runs on a platform with async TSC
resets as documented in commit 341102c3ef29 ("x86/tsc: Add option that TSC
on Socket 0 being non-zero is valid")
Fix it by skipping the early tsc initialization on UV systems and let TSC
init tests take place later in tsc_init().
Fixes: cf7a63ef4e02 ("x86/tsc: Calibrate tsc only once")
Suggested-by: Hedi Berriche <hedi.berriche@hpe.com>
Signed-off-by: Mike Travis <mike.travis@hpe.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Russ Anderson <rja@hpe.com>
Reviewed-by: Dimitri Sivanich <sivanich@hpe.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Russ Anderson <russ.anderson@hpe.com>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: Xiaoming Gao <gxm.linux.kernel@gmail.com>
Cc: Rajvi Jingar <rajvi.jingar@intel.com>
Link: https://lkml.kernel.org/r/20181002180144.923579706@stormcage.americas.sgi.com
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Introduce is_early_uv_system() which uses efi.uv_systab to decide early
in the boot process whether the kernel runs on a UV system.
This is needed to skip other early setup/init code that might break
the UV platform if done too early such as before necessary ACPI tables
parsing takes place.
Suggested-by: Hedi Berriche <hedi.berriche@hpe.com>
Signed-off-by: Mike Travis <mike.travis@hpe.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Russ Anderson <rja@hpe.com>
Reviewed-by: Dimitri Sivanich <sivanich@hpe.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Russ Anderson <russ.anderson@hpe.com>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: Xiaoming Gao <gxm.linux.kernel@gmail.com>
Cc: Rajvi Jingar <rajvi.jingar@intel.com>
Link: https://lkml.kernel.org/r/20181002180144.801700401@stormcage.americas.sgi.com
|
|
When FW floods the driver with control messages try to exit the cmsg
processing loop every now and then to avoid soft lockups. Cmsg
processing is generally very lightweight so 512 seems like a reasonable
budget, which should not be exceeded under normal conditions.
Fixes: 77ece8d5f196 ("nfp: add control vNIC datapath")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Tested-by: Pieter Jansen van Vuuren <pieter.jansenvanvuuren@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
Fix a commit 4bcc595ccd80 ("printk: reinstate KERN_CONT for printing
continuation lines") regression with the `declance' driver, which caused
the adapter identification message to be split between two lines, e.g.:
declance.c: v0.011 by Linux MIPS DECstation task force
tc6: PMAD-AA
, addr = 08:00:2b:1b:2a:6a, irq = 14
tc6: registered as eth0.
Address that properly, by printing identification with a single call,
making the messages now look like:
declance.c: v0.011 by Linux MIPS DECstation task force
tc6: PMAD-AA, addr = 08:00:2b:1b:2a:6a, irq = 14
tc6: registered as eth0.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Fixes: 4bcc595ccd80 ("printk: reinstate KERN_CONT for printing continuation lines")
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
During certain heavy network loads TX could time out
with TX ring dump.
TX is sometimes never restarted after reaching
"tx_stop_threshold" because function "fec_enet_tx_queue"
only tests the first queue.
In addition the TX timeout callback function failed to
recover because it also operated only on the first queue.
Signed-off-by: Rickard x Andersson <rickaran@axis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
If IOMMU is enabled and Thunderbolt driver is built into the kernel
image, it will be probed before IOMMUs are attached to the PCI bus.
Because of this DMA mappings the driver does will not go through IOMMU
and start failing right after IOMMUs are enabled.
For this reason move the Thunderbolt driver initialization happen at
rootfs level.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
If there is a long chain of devices connected when the driver is loaded
ICM sends device connected event for each and those are put to tb->wq
for later processing. Now if the driver gets unloaded in the middle, so
that the work queue is not yet empty it gets flushed by tb_domain_stop().
However, by that time the root switch is already removed so the driver
crashes when it tries to dereference it in ICM event handling callbacks.
Fix this by checking whether the root switch is already removed. If it
is we know that the domain is stopped and we should merely skip handling
the event.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Casting address to unsigned int causes a warning on some 64 bit
architectures. Fix the cast.
Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Mark Brown <broonie@kernel.org>
|
|
Replace "fallthru" with a proper "fall through" annotation.
This fix is part of the ongoing efforts to enabling
-Wimplicit-fallthrough
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
|
This avoids a warning on powerpc.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
|
|
Commit 51c3c62b58b3 ("powerpc: Avoid code patching freed init
sections") accesses 'init_mem_is_free' flag too early, before the
kernel is relocated. This provokes early boot failure (before the
console is active).
As it is not necessary to do this verification that early, this
patch moves the test into patch_instruction() instead of
__patch_instruction().
This modification also has the advantage of avoiding unnecessary
remappings.
Fixes: 51c3c62b58b3 ("powerpc: Avoid code patching freed init sections")
Cc: stable@vger.kernel.org # 4.13+
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
|
|
commit efdfeb079cc3
("regulator: fixed: Convert to use GPIO descriptor only")
switched to use gpiod_get() to look up the regulator from the
gpiolib core whether that is device tree or boardfile.
This meant that we activate the code in
a603a2b8d86e ("gpio: of: Add special quirk to parse regulator flags")
which means the descriptors coming from the device tree already
have the right inversion and open drain semantics set up from
the gpiolib core.
As the fixed regulator was inspected again we got the
inverted inversion and things broke.
Fix it by ignoring the config in the device tree for now: the
later patches in the series will push all inversion handling
over to the gpiolib core and set it up properly in the
boardfiles for legacy devices, but I did not finish that
for this kernel cycle.
Fixes: commit efdfeb079cc3 ("regulator: fixed: Convert to use GPIO descriptor only")
Reported-by: Leonard Crestez <leonard.crestez@nxp.com>
Reported-by: Fabio Estevam <festevam@gmail.com>
Reported-by: John Stultz <john.stultz@linaro.org>
Reported-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
|
|
Explicitly forbid creating cgroup local storage maps with zero value
size, as it makes no sense and might even cause a panic.
Reported-by: syzbot+18628320d3b14a5c459c@syzkaller.appspotmail.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
|
|
Bartlomiej writes:
"fbdev fixes for v4.19-rc7:
- fix OMAPFB_MEMORY_READ ioctl to not leak kernel memory in omapfb driver
(Tomi Valkeinen)
- add missing prepare/unprepare clock operations in pxa168fb driver
(Lubomir Rintel)
- add nobgrt option in efifb driver to disable ACPI BGRT logo restore
(Hans de Goede)
- fix spelling mistake in fall-through annotation in stifb driver
(Gustavo A. R. Silva)
- fix URL for uvesafb repository in the documentation (Adam Jackson)"
* tag 'fbdev-v4.19-rc7' of https://github.com/bzolnier/linux:
video/fbdev/stifb: Fix spelling mistake in fall-through annotation
uvesafb: Fix URLs in the documentation
efifb: BGRT: Add nobgrt option
fbdev/omapfb: fix omapfb_memory_read infoleak
pxa168fb: prepare the clock
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|
git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc
Ulf writes:
"MMC core:
- Fixup conversion of debounce time to/from ms/us
MMC host:
- sdhi: Fixup whitelisting for Gen3 types"
* tag 'mmc-v4.19-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc:
mmc: slot-gpio: Fix debounce time to use miliseconds again
mmc: core: Fix debounce time to use microseconds
mmc: sdhi: sys_dmac: check for all Gen3 types when whitelisting
|
|
Sergey Suloev reported a crash happening in drm_client_dev_hotplug()
when fbdev had failed to register.
[ 9.124598] vc4_hdmi 3f902000.hdmi: ASoC: Failed to create component debugfs directory
[ 9.147667] vc4_hdmi 3f902000.hdmi: vc4-hdmi-hifi <-> 3f902000.hdmi mapping ok
[ 9.155184] vc4_hdmi 3f902000.hdmi: ASoC: no DMI vendor name!
[ 9.166544] vc4-drm soc:gpu: bound 3f902000.hdmi (ops vc4_hdmi_ops [vc4])
[ 9.173840] vc4-drm soc:gpu: bound 3f806000.vec (ops vc4_vec_ops [vc4])
[ 9.181029] vc4-drm soc:gpu: bound 3f004000.txp (ops vc4_txp_ops [vc4])
[ 9.188519] vc4-drm soc:gpu: bound 3f400000.hvs (ops vc4_hvs_ops [vc4])
[ 9.195690] vc4-drm soc:gpu: bound 3f206000.pixelvalve (ops vc4_crtc_ops [vc4])
[ 9.203523] vc4-drm soc:gpu: bound 3f207000.pixelvalve (ops vc4_crtc_ops [vc4])
[ 9.215032] vc4-drm soc:gpu: bound 3f807000.pixelvalve (ops vc4_crtc_ops [vc4])
[ 9.274785] vc4-drm soc:gpu: bound 3fc00000.v3d (ops vc4_v3d_ops [vc4])
[ 9.290246] [drm] Initialized vc4 0.0.0 20140616 for soc:gpu on minor 0
[ 9.297464] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[ 9.304600] [drm] Driver supports precise vblank timestamp query.
[ 9.382856] vc4-drm soc:gpu: [drm:drm_fb_helper_fbdev_setup [drm_kms_helper]] *ERROR* Failed to set fbdev configuration
[ 10.404937] Unable to handle kernel paging request at virtual address 00330a656369768a
[ 10.441620] [00330a656369768a] address between user and kernel address ranges
[ 10.449087] Internal error: Oops: 96000004 [#1] PREEMPT SMP
[ 10.454762] Modules linked in: brcmfmac vc4 drm_kms_helper cfg80211 drm rfkill smsc95xx brcmutil usbnet drm_panel_orientation_quirks raspberrypi_hwmon bcm2835_dma crc32_ce pwm_bcm2835 bcm2835_rng virt_dma rng_core i2c_bcm2835 ip_tables x_tables ipv6
[ 10.477296] CPU: 2 PID: 45 Comm: kworker/2:1 Not tainted 4.19.0-rc5 #3
[ 10.483934] Hardware name: Raspberry Pi 3 Model B Rev 1.2 (DT)
[ 10.489966] Workqueue: events output_poll_execute [drm_kms_helper]
[ 10.596515] Process kworker/2:1 (pid: 45, stack limit = 0x000000007e8924dc)
[ 10.603590] Call trace:
[ 10.606259] drm_client_dev_hotplug+0x5c/0xb0 [drm]
[ 10.611303] drm_kms_helper_hotplug_event+0x30/0x40 [drm_kms_helper]
[ 10.617849] output_poll_execute+0xc4/0x1e0 [drm_kms_helper]
[ 10.623616] process_one_work+0x1c8/0x318
[ 10.627695] worker_thread+0x48/0x428
[ 10.631420] kthread+0xf8/0x128
[ 10.634615] ret_from_fork+0x10/0x18
[ 10.638255] Code: 54000220 f9401261 aa1303e0 b4000141 (f9400c21)
[ 10.644456] ---[ end trace c75b4a4b0e141908 ]---
The reason for this is that drm_fbdev_cma_init() removes the drm_client
when fbdev registration fails, but it doesn't remove the client from the
drm_device client list. So the client list now has a pointer that points
into the unknown and we have a 'use after free' situation.
Split drm_client_new() into drm_client_init() and drm_client_add() to fix
removal in the error path.
Fixes: 894a677f4b3e ("drm/cma-helper: Use the generic fbdev emulation")
Reported-by: Sergey Suloev <ssuloev@orpaltech.com>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Eric Anholt <eric@anholt.net>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20181001194536.57756-1-noralf@tronnes.org
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Add pins, groups, and function for the Interrupt Controller for
External Devices (INTC-EX) on the R-Car E3 SoC.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
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This provides a pinctrl driver for the Renesas RZ/N1 device family.
Based on a patch originally written by Michel Pollet at Renesas.
Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
|
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The Renesas RZ/N1 device family PINCTRL node description.
Based on a patch originally written by Michel Pollet at Renesas.
Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
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Automatic NUMA Balancing uses a multi-stage pass to decide whether a page
should migrate to a local node. This filter avoids excessive ping-ponging
if a page is shared or used by threads that migrate cross-node frequently.
Threads inherit both page tables and the preferred node ID from the
parent. This means that threads can trigger hinting faults earlier than
a new task which delays scanning for a number of seconds. As it can be
load balanced very early in its lifetime there can be an unnecessary delay
before it starts migrating thread-local data. This patch migrates private
pages faster early in the lifetime of a thread using the sequence counter
as an identifier of new tasks.
With this patch applied, STREAM performance is the same as 4.17 even though
processes are not spread cross-node prematurely. Other workloads showed
a mix of minor gains and losses. This is somewhat expected most workloads
are not very sensitive to the starting conditions of a process.
4.19.0-rc5 4.19.0-rc5 4.17.0
numab-v1r1 fastmigrate-v1r1 vanilla
MB/sec copy 43298.52 ( 0.00%) 47335.46 ( 9.32%) 47219.24 ( 9.06%)
MB/sec scale 30115.06 ( 0.00%) 32568.12 ( 8.15%) 32527.56 ( 8.01%)
MB/sec add 32825.12 ( 0.00%) 36078.94 ( 9.91%) 35928.02 ( 9.45%)
MB/sec triad 32549.52 ( 0.00%) 35935.94 ( 10.40%) 35969.88 ( 10.51%)
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Rik van Riel <riel@surriel.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Jirka Hladky <jhladky@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux-MM <linux-mm@kvack.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20181001100525.29789-3-mgorman@techsingularity.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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|
Rate limiting of page migrations due to automatic NUMA balancing was
introduced to mitigate the worst-case scenario of migrating at high
frequency due to false sharing or slowly ping-ponging between nodes.
Since then, a lot of effort was spent on correctly identifying these
pages and avoiding unnecessary migrations and the safety net may no longer
be required.
Jirka Hladky reported a regression in 4.17 due to a scheduler patch that
avoids spreading STREAM tasks wide prematurely. However, once the task
was properly placed, it delayed migrating the memory due to rate limiting.
Increasing the limit fixed the problem for him.
Currently, the limit is hard-coded and does not account for the real
capabilities of the hardware. Even if an estimate was attempted, it would
not properly account for the number of memory controllers and it could
not account for the amount of bandwidth used for normal accesses. Rather
than fudging, this patch simply eliminates the rate limiting.
However, Jirka reports that a STREAM configuration using multiple
processes achieved similar performance to 4.16. In local tests, this patch
improved performance of STREAM relative to the baseline but it is somewhat
machine-dependent. Most workloads show little or not performance difference
implying that there is not a heavily reliance on the throttling mechanism
and it is safe to remove.
STREAM on 2-socket machine
4.19.0-rc5 4.19.0-rc5
numab-v1r1 noratelimit-v1r1
MB/sec copy 43298.52 ( 0.00%) 44673.38 ( 3.18%)
MB/sec scale 30115.06 ( 0.00%) 31293.06 ( 3.91%)
MB/sec add 32825.12 ( 0.00%) 34883.62 ( 6.27%)
MB/sec triad 32549.52 ( 0.00%) 34906.60 ( 7.24%
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Rik van Riel <riel@surriel.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Jirka Hladky <jhladky@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux-MM <linux-mm@kvack.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20181001100525.29789-2-mgorman@techsingularity.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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|
Fix incorrect line number in example output
Signed-off-by: Andrew Murray <andrew.murray@arm.com>
Cc: Jiri Kosina <trivial@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-doc@vger.kernel.org
Link: http://lkml.kernel.org/r/1538391663-54524-1-git-send-email-andrew.murray@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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|
This code needs to select function #0, which is the first int in the
array of functions, not the number 0 which may or may not be the
function for "GPIO mode" per the enum mapping. We were getting lucky on
SDM845, where this was tested, because the function 0 matched the enum
value for "GPIO mode". On other platforms, e.g. MSM8996, the gpio enum
value is the last one in the list so this code doesn't work and we see a
warning at boot. Fix it by grabbing the first element out of the array
of functions.
Cc: Doug Anderson <dianders@chromium.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Niklas Cassel <niklas.cassel@linaro.org>
Reported-by: Niklas Cassel <niklas.cassel@linaro.org>
Fixes: 1de7ddb3a15c ("pinctrl: msm: Mux out gpio function with gpio_request()")
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Tested-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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Since 890658b7ab48 ("locking/mutex: Kill arch specific code"), there
are no mutex header files under arch/, so we can remove the redundant
entry from MAINTAINERS.
Reported-by: Joe Perches <joe@perches.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Jason Low <jason.low2@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20181001142856.GC9716@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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|
Amend the changes in commit:
1f03e8d2919270 ("locking/barriers: Replace smp_cond_acquire() with smp_cond_load_acquire()")
... by updating the documentation accordingly.
Also remove some obsolete information related to the implementation.
Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Akira Yokosawa <akiyks@gmail.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Daniel Lustig <dlustig@nvidia.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Jade Alglave <j.alglave@ucl.ac.uk>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luc Maranget <luc.maranget@inria.fr>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-arch@vger.kernel.org
Cc: parri.andrea@gmail.com
Link: http://lkml.kernel.org/r/20180926182920.27644-5-paulmck@linux.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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This commit adds more detail about compiler optimizations and
not-yet-modeled Linux-kernel APIs.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Andrea Parri <andrea.parri@amarulasolutions.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: akiyks@gmail.com
Cc: boqun.feng@gmail.com
Cc: dhowells@redhat.com
Cc: j.alglave@ucl.ac.uk
Cc: linux-arch@vger.kernel.org
Cc: luc.maranget@inria.fr
Cc: npiggin@gmail.com
Cc: parri.andrea@gmail.com
Cc: stern@rowland.harvard.edu
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/20180926182920.27644-4-paulmck@linux.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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This commit fixes a duplicate-"the" typo in README.
Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: akiyks@gmail.com
Cc: boqun.feng@gmail.com
Cc: dhowells@redhat.com
Cc: j.alglave@ucl.ac.uk
Cc: linux-arch@vger.kernel.org
Cc: luc.maranget@inria.fr
Cc: npiggin@gmail.com
Cc: parri.andrea@gmail.com
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/20180926182920.27644-3-paulmck@linux.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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release/acquire
More than one kernel developer has expressed the opinion that the LKMM
should enforce ordering of writes by locking. In other words, given
the following code:
WRITE_ONCE(x, 1);
spin_unlock(&s):
spin_lock(&s);
WRITE_ONCE(y, 1);
the stores to x and y should be propagated in order to all other CPUs,
even though those other CPUs might not access the lock s. In terms of
the memory model, this means expanding the cumul-fence relation.
Locks should also provide read-read (and read-write) ordering in a
similar way. Given:
READ_ONCE(x);
spin_unlock(&s);
spin_lock(&s);
READ_ONCE(y); // or WRITE_ONCE(y, 1);
the load of x should be executed before the load of (or store to) y.
The LKMM already provides this ordering, but it provides it even in
the case where the two accesses are separated by a release/acquire
pair of fences rather than unlock/lock. This would prevent
architectures from using weakly ordered implementations of release and
acquire, which seems like an unnecessary restriction. The patch
therefore removes the ordering requirement from the LKMM for that
case.
There are several arguments both for and against this change. Let us
refer to these enhanced ordering properties by saying that the LKMM
would require locks to be RCtso (a bit of a misnomer, but analogous to
RCpc and RCsc) and it would require ordinary acquire/release only to
be RCpc. (Note: In the following, the phrase "all supported
architectures" is meant not to include RISC-V. Although RISC-V is
indeed supported by the kernel, the implementation is still somewhat
in a state of flux and therefore statements about it would be
premature.)
Pros:
The kernel already provides RCtso ordering for locks on all
supported architectures, even though this is not stated
explicitly anywhere. Therefore the LKMM should formalize it.
In theory, guaranteeing RCtso ordering would reduce the need
for additional barrier-like constructs meant to increase the
ordering strength of locks.
Will Deacon and Peter Zijlstra are strongly in favor of
formalizing the RCtso requirement. Linus Torvalds and Will
would like to go even further, requiring locks to have RCsc
behavior (ordering preceding writes against later reads), but
they recognize that this would incur a noticeable performance
degradation on the POWER architecture. Linus also points out
that people have made the mistake, in the past, of assuming
that locking has stronger ordering properties than is
currently guaranteed, and this change would reduce the
likelihood of such mistakes.
Not requiring ordinary acquire/release to be any stronger than
RCpc may prove advantageous for future architectures, allowing
them to implement smp_load_acquire() and smp_store_release()
with more efficient machine instructions than would be
possible if the operations had to be RCtso. Will and Linus
approve this rationale, hypothetical though it is at the
moment (it may end up affecting the RISC-V implementation).
The same argument may or may not apply to RMW-acquire/release;
see also the second Con entry below.
Linus feels that locks should be easy for people to use
without worrying about memory consistency issues, since they
are so pervasive in the kernel, whereas acquire/release is
much more of an "experts only" tool. Requiring locks to be
RCtso is a step in this direction.
Cons:
Andrea Parri and Luc Maranget think that locks should have the
same ordering properties as ordinary acquire/release (indeed,
Luc points out that the names "acquire" and "release" derive
from the usage of locks). Andrea points out that having
different ordering properties for different forms of acquires
and releases is not only unnecessary, it would also be
confusing and unmaintainable.
Locks are constructed from lower-level primitives, typically
RMW-acquire (for locking) and ordinary release (for unlock).
It is illogical to require stronger ordering properties from
the high-level operations than from the low-level operations
they comprise. Thus, this change would make
while (cmpxchg_acquire(&s, 0, 1) != 0)
cpu_relax();
an incorrect implementation of spin_lock(&s) as far as the
LKMM is concerned. In theory this weakness can be ameliorated
by changing the LKMM even further, requiring
RMW-acquire/release also to be RCtso (which it already is on
all supported architectures).
As far as I know, nobody has singled out any examples of code
in the kernel that actually relies on locks being RCtso.
(People mumble about RCU and the scheduler, but nobody has
pointed to any actual code. If there are any real cases,
their number is likely quite small.) If RCtso ordering is not
needed, why require it?
A handful of locking constructs (qspinlocks, qrwlocks, and
mcs_spinlocks) are built on top of smp_cond_load_acquire()
instead of an RMW-acquire instruction. It currently provides
only the ordinary acquire semantics, not the stronger ordering
this patch would require of locks. In theory this could be
ameliorated by requiring smp_cond_load_acquire() in
combination with ordinary release also to be RCtso (which is
currently true on all supported architectures).
On future weakly ordered architectures, people may be able to
implement locks in a non-RCtso fashion with significant
performance improvement. Meeting the RCtso requirement would
necessarily add run-time overhead.
Overall, the technical aspects of these arguments seem relatively
minor, and it appears mostly to boil down to a matter of opinion.
Since the opinions of senior kernel maintainers such as Linus,
Peter, and Will carry more weight than those of Luc and Andrea, this
patch changes the model in accordance with the maintainers' wishes.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Andrea Parri <andrea.parri@amarulasolutions.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: akiyks@gmail.com
Cc: boqun.feng@gmail.com
Cc: dhowells@redhat.com
Cc: j.alglave@ucl.ac.uk
Cc: linux-arch@vger.kernel.org
Cc: luc.maranget@inria.fr
Cc: npiggin@gmail.com
Cc: parri.andrea@gmail.com
Link: http://lkml.kernel.org/r/20180926182920.27644-2-paulmck@linux.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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This commit documents the scheme used to generate the names for the
litmus tests.
[ paulmck: Apply feedback from Andrea Parri and Will Deacon. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: akiyks@gmail.com
Cc: boqun.feng@gmail.com
Cc: dhowells@redhat.com
Cc: j.alglave@ucl.ac.uk
Cc: linux-arch@vger.kernel.org
Cc: luc.maranget@inria.fr
Cc: npiggin@gmail.com
Cc: parri.andrea@gmail.com
Cc: stern@rowland.harvard.edu
Link: http://lkml.kernel.org/r/20180926182920.27644-1-paulmck@linux.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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fd_install() moves the reference given to it into the file descriptor table
of the current process. If the current process is multithreaded, then
immediately after fd_install(), another thread can close() the file
descriptor and cause the file's resources to be cleaned up.
Since the reference to "lessee" is held by the file, we must not access
"lessee" after the fd_install() call.
As far as I can tell, to reach this codepath, the caller must have an open
file descriptor to a DRI device in master mode. I'm not sure what the
requirements for that are.
Signed-off-by: Jann Horn <jannh@google.com>
Fixes: 62884cd386b8 ("drm: Add four ioctls for managing drm mode object leases [v7]")
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20181001153117.216923-1-jannh@google.com
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