commit db6c3c064f upstream.
Add the missing endpoint max-packet sanity check to probe() to avoid
division by zero in lan78xx_tx_bh() in case a malicious device has
broken descriptors (or when doing descriptor fuzz testing).
Note that USB core will reject URBs submitted for endpoints with zero
wMaxPacketSize but that drivers doing packet-size calculations still
need to handle this (cf. commit 2548288b4f ("USB: Fix: Don't skip
endpoint descriptors with maxpacket=0")).
Fixes: 55d7de9de6 ("Microchip's LAN7800 family USB 2/3 to 10/100/1000 Ethernet device driver")
Cc: stable@vger.kernel.org # 4.3
Cc: Woojung.Huh@microchip.com <Woojung.Huh@microchip.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9af372dc70 upstream.
To reset standard tuning circuit completely, after clear ESDHC_MIX_CTRL_EXE_TUNE,
also need to clear bit buffer_read_ready, this operation will finally clear the
USDHC IP internal logic flag execute_tuning_with_clr_buf, make sure the following
normal data transfer will not be impacted by standard tuning logic used before.
Find this issue when do quick SD card insert/remove stress test. During standard
tuning prodedure, if remove SD card, USDHC standard tuning logic can't clear the
internal flag execute_tuning_with_clr_buf. Next time when insert SD card, all
data related commands can't get any data related interrupts, include data transfer
complete interrupt, data timeout interrupt, data CRC interrupt, data end bit interrupt.
Always trigger software timeout issue. Even reset the USDHC through bits in register
SYS_CTRL (0x2C, bit28 reset tuning, bit26 reset data, bit 25 reset command, bit 24
reset all) can't recover this. From the user's point of view, USDHC stuck, SD can't
be recognized any more.
Fixes: d9370424c9 ("mmc: sdhci-esdhc-imx: reset tuning circuit when power on mmc card")
Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/1634263236-6111-1-git-send-email-haibo.chen@nxp.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 92b18252b9 upstream.
While mmc0 enter suspend state, we need halt CQE to send legacy cmd(flush
cache) and disable cqe, for resume back, we enable CQE and not clear HALT
state.
In this case MediaTek mmc host controller will keep the value for HALT
state after CQE disable/enable flow, so the next CQE transfer after resume
will be timeout due to CQE is in HALT state, the log as below:
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: timeout for tag 2
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: ============ CQHCI REGISTER DUMP ===========
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: Caps: 0x100020b6 | Version: 0x00000510
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: Config: 0x00001103 | Control: 0x00000001
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: Int stat: 0x00000000 | Int enab: 0x00000006
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: Int sig: 0x00000006 | Int Coal: 0x00000000
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: TDL base: 0xfd05f000 | TDL up32: 0x00000000
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: Doorbell: 0x8000203c | TCN: 0x00000000
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: Dev queue: 0x00000000 | Dev Pend: 0x00000000
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: Task clr: 0x00000000 | SSC1: 0x00001000
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: SSC2: 0x00000001 | DCMD rsp: 0x00000000
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: RED mask: 0xfdf9a080 | TERRI: 0x00000000
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: Resp idx: 0x00000000 | Resp arg: 0x00000000
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: CRNQP: 0x00000000 | CRNQDUN: 0x00000000
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: CRNQIS: 0x00000000 | CRNQIE: 0x00000000
This change check HALT state after CQE enable, if CQE is in HALT state, we
will clear it.
Signed-off-by: Wenbin Mei <wenbin.mei@mediatek.com>
Cc: stable@vger.kernel.org
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Fixes: a4080225f5 ("mmc: cqhci: support for command queue enabled host")
Link: https://lore.kernel.org/r/20211026070812.9359-1-wenbin.mei@mediatek.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit da353fac65 upstream.
sk->sk_err appears to expect a positive value, a convention that ktls
doesn't always follow and that leads to memory corruption in other code.
For instance,
[kworker]
tls_encrypt_done(..., err=<negative error from crypto request>)
tls_err_abort(.., err)
sk->sk_err = err;
[task]
splice_from_pipe_feed
...
tls_sw_do_sendpage
if (sk->sk_err) {
ret = -sk->sk_err; // ret is positive
splice_from_pipe_feed (continued)
ret = actor(...) // ret is still positive and interpreted as bytes
// written, resulting in underflow of buf->len and
// sd->len, leading to huge buf->offset and bogus
// addresses computed in later calls to actor()
Fix all tls_err_abort() callers to pass a negative error code
consistently and centralize the error-prone sign flip there, throwing in
a warning to catch future misuse and uninlining the function so it
really does only warn once.
Cc: stable@vger.kernel.org
Fixes: c46234ebb4 ("tls: RX path for ktls")
Reported-by: syzbot+b187b77c8474f9648fae@syzkaller.appspotmail.com
Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 2195f2062e upstream.
During probing, the driver tries to get a list (mask) of supported
command types in port100_get_command_type_mask() function. The value
is u64 and 0 is treated as invalid mask (no commands supported). The
function however returns also -ERRNO as u64 which will be interpret as
valid command mask.
Return 0 on every error case of port100_get_command_type_mask(), so the
probing will stop.
Cc: <stable@vger.kernel.org>
Fixes: 0347a6ab30 ("NFC: port100: Commands mechanism implementation")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a0023bb9dd upstream.
mv_init_host() propagates the value returned by mv_chip_id() which in turn
gets propagated by mv_pci_init_one() and hits local_pci_probe().
During the process of driver probing, the probe function should return < 0
for failure, otherwise, the kernel will treat value > 0 as success.
Since this is a bug rather than a recoverable runtime error we should
use dev_alert() instead of dev_err().
Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6dba4bdfd7 upstream.
This reverts commit a49d784d5a.
The updated binding was wrong / invalid and has been reverted. There
isn't any upstream kernel DTS using it and Broadcom isn't known to use
it neither. There is close to zero chance this will cause regression for
anyone.
Actually in-kernel bcm5301x.dtsi still uses the old good binding and so
it's broken since the driver update. This revert fixes it.
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Link: https://lore.kernel.org/r/20211008205938.29925-3-zajec5@gmail.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6457378fe7 upstream.
A group of security researchers brought to our attention
the weakness of hash function used in fnhe_hashfun().
Lets use siphash instead of Jenkins Hash, to considerably
reduce security risks.
Also remove the inline keyword, this really is distracting.
Fixes: d546c62154 ("ipv4: harden fnhe_hashfun()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Keyu Man <kman001@ucr.edu>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: David S. Miller <davem@davemloft.net>
[OP: adjusted context for 5.4 stable]
Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4785305c05 upstream.
A group of security researchers brought to our attention
the weakness of hash function used in rt6_exception_hash()
Lets use siphash instead of Jenkins Hash, to considerably
reduce security risks.
Following patch deals with IPv4.
Fixes: 35732d01fe ("ipv6: introduce a hash table to store dst cache")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Keyu Man <kman001@ucr.edu>
Cc: Wei Wang <weiwan@google.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Acked-by: Wei Wang <weiwan@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[OP: adjusted context for 5.4 stable]
Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 48ccc8edf5 upstream.
In randconfig builds, we sometimes come across this warning:
arm-linux-gnueabi-ld: XIP start address may cause MPU programming issues
While this is helpful for actual systems to figure out why it
fails, the warning does not provide any benefit for build testing,
so guard it in a check for CONFIG_COMPILE_TEST, which is usually
set on randconfig builds.
Fixes: 216218308c ("ARM: 8713/1: NOMMU: Support MPU in XIP configuration")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit eaf6cc7165 upstream.
Both the decompressor code and the kasan logic try to override
the memcpy() and memmove() definitions, which leading to a clash
in a KASAN-enabled kernel with XZ decompression:
arch/arm/boot/compressed/decompress.c:50:9: error: 'memmove' macro redefined [-Werror,-Wmacro-redefined]
#define memmove memmove
^
arch/arm/include/asm/string.h:59:9: note: previous definition is here
#define memmove(dst, src, len) __memmove(dst, src, len)
^
arch/arm/boot/compressed/decompress.c:51:9: error: 'memcpy' macro redefined [-Werror,-Wmacro-redefined]
#define memcpy memcpy
^
arch/arm/include/asm/string.h:58:9: note: previous definition is here
#define memcpy(dst, src, len) __memcpy(dst, src, len)
^
Here we want the set of functions from the decompressor, so undefine
the other macros before the override.
Link: https://lore.kernel.org/linux-arm-kernel/CACRpkdZYJogU_SN3H9oeVq=zJkRgRT1gDz3xp59gdqWXxw-B=w@mail.gmail.com/
Link: https://lore.kernel.org/lkml/202105091112.F5rmd4By-lkp@intel.com/
Fixes: d6d51a96c7 ("ARM: 9014/2: Replace string mem* functions for KASan")
Fixes: a7f464f3db ("ARM: 7001/2: Wire up support for the XZ decompressor")
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9d417cbe36 upstream.
tglx notes:
This function [futex_detect_cmpxchg] is only needed when an
architecture has to runtime discover whether the CPU supports it or
not. ARM has unconditional support for this, so the obvious thing to
do is the below.
Fixes linkage failure from Clang randconfigs:
kernel/futex.o:(.text.fixup+0x5c): relocation truncated to fit: R_ARM_JUMP24 against `.init.text'
and boot failures for CONFIG_THUMB2_KERNEL.
Link: https://github.com/ClangBuiltLinux/linux/issues/325
Comments from Nick Desaulniers:
See-also: 03b8c7b623 ("futex: Allow architectures to skip
futex_atomic_cmpxchg_inatomic() test")
Reported-by: Arnd Bergmann <arnd@arndb.de>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Cc: stable@vger.kernel.org # v3.14+
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ed65df63a3 upstream.
While writing an email explaining the "bit = 0" logic for a discussion on
making ftrace_test_recursion_trylock() disable preemption, I discovered a
path that makes the "not do the logic if bit is zero" unsafe.
The recursion logic is done in hot paths like the function tracer. Thus,
any code executed causes noticeable overhead. Thus, tricks are done to try
to limit the amount of code executed. This included the recursion testing
logic.
Having recursion testing is important, as there are many paths that can
end up in an infinite recursion cycle when tracing every function in the
kernel. Thus protection is needed to prevent that from happening.
Because it is OK to recurse due to different running context levels (e.g.
an interrupt preempts a trace, and then a trace occurs in the interrupt
handler), a set of bits are used to know which context one is in (normal,
softirq, irq and NMI). If a recursion occurs in the same level, it is
prevented*.
Then there are infrastructure levels of recursion as well. When more than
one callback is attached to the same function to trace, it calls a loop
function to iterate over all the callbacks. Both the callbacks and the
loop function have recursion protection. The callbacks use the
"ftrace_test_recursion_trylock()" which has a "function" set of context
bits to test, and the loop function calls the internal
trace_test_and_set_recursion() directly, with an "internal" set of bits.
If an architecture does not implement all the features supported by ftrace
then the callbacks are never called directly, and the loop function is
called instead, which will implement the features of ftrace.
Since both the loop function and the callbacks do recursion protection, it
was seemed unnecessary to do it in both locations. Thus, a trick was made
to have the internal set of recursion bits at a more significant bit
location than the function bits. Then, if any of the higher bits were set,
the logic of the function bits could be skipped, as any new recursion
would first have to go through the loop function.
This is true for architectures that do not support all the ftrace
features, because all functions being traced must first go through the
loop function before going to the callbacks. But this is not true for
architectures that support all the ftrace features. That's because the
loop function could be called due to two callbacks attached to the same
function, but then a recursion function inside the callback could be
called that does not share any other callback, and it will be called
directly.
i.e.
traced_function_1: [ more than one callback tracing it ]
call loop_func
loop_func:
trace_recursion set internal bit
call callback
callback:
trace_recursion [ skipped because internal bit is set, return 0 ]
call traced_function_2
traced_function_2: [ only traced by above callback ]
call callback
callback:
trace_recursion [ skipped because internal bit is set, return 0 ]
call traced_function_2
[ wash, rinse, repeat, BOOM! out of shampoo! ]
Thus, the "bit == 0 skip" trick is not safe, unless the loop function is
call for all functions.
Since we want to encourage architectures to implement all ftrace features,
having them slow down due to this extra logic may encourage the
maintainers to update to the latest ftrace features. And because this
logic is only safe for them, remove it completely.
[*] There is on layer of recursion that is allowed, and that is to allow
for the transition between interrupt context (normal -> softirq ->
irq -> NMI), because a trace may occur before the context update is
visible to the trace recursion logic.
Link: https://lore.kernel.org/all/609b565a-ed6e-a1da-f025-166691b5d994@linux.alibaba.com/
Link: https://lkml.kernel.org/r/20211018154412.09fcad3c@gandalf.local.home
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@hansenpartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Jisheng Zhang <jszhang@kernel.org>
Cc: =?utf-8?b?546L6LSH?= <yun.wang@linux.alibaba.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: stable@vger.kernel.org
Fixes: edc15cafcb ("tracing: Avoid unnecessary multiple recursion checks")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit d997cc1715 ]
On i.MX7S and i.MX8M* (but not i.MX6*) the pwrkey device has an
associated clock. Accessing the registers requires that this clock is
enabled. Binding the driver on at least i.MX7S and i.MX8MP while not
having the clock enabled results in a complete hang of the machine.
(This usually only happens if snvs_pwrkey is built as a module and the
rtc-snvs driver isn't already bound because at bootup the required clk
is on and only gets disabled when the clk framework disables unused clks
late during boot.)
This completes the fix in commit 135be16d35 ("ARM: dts: imx7s: add
snvs clock to pwrkey").
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20211013062848.2667192-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit b37a15188e ]
The snd_hdac_bus_reset_link() contains logic to clear STATESTS register
before performing controller reset. This code dates back to an old
bugfix in commit e8a7f136f5 ("[ALSA] hda-intel - Improve HD-audio
codec probing robustness"). Originally the code was added to
azx_reset().
The code was moved around in commit a41d122449 ("ALSA: hda - Embed bus
into controller object") and ended up to snd_hdac_bus_reset_link() and
called primarily via snd_hdac_bus_init_chip().
The logic to clear STATESTS is correct when snd_hdac_bus_init_chip() is
called when controller is not in reset. In this case, STATESTS can be
cleared. This can be useful e.g. when forcing a controller reset to retry
codec probe. A normal non-power-on reset will not clear the bits.
However, this old logic is problematic when controller is already in
reset. The HDA specification states that controller must be taken out of
reset before writing to registers other than GCTL.CRST (1.0a spec,
3.3.7). The write to STATESTS in snd_hdac_bus_reset_link() will be lost
if the controller is already in reset per the HDA specification mentioned.
This has been harmless on older hardware. On newer generation of Intel
PCIe based HDA controllers, if configured to report issues, this write
will emit an unsupported request error. If ACPI Platform Error Interface
(APEI) is enabled in kernel, this will end up to kernel log.
Fix the code in snd_hdac_bus_reset_link() to only clear the STATESTS if
the function is called when controller is not in reset. Otherwise
clearing the bits is not possible and should be skipped.
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://lore.kernel.org/r/20211012142935.3731820-1-kai.vehmanen@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 6636fec29c ]
On SPEAr3xx, ethernet driver is not compatible with the SPEAr600
one.
Indeed, SPEAr3xx uses an earlier version of this IP (v3.40) and
needs some driver tuning compare to SPEAr600.
The v3.40 IP support was added to stmmac driver and this patch
fixes this issue and use the correct compatible string for
SPEAr3xx
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 77a5b9e3d1 ]
Currently inode_in_dir() ignores errors returned from
btrfs_lookup_dir_index_item() and from btrfs_lookup_dir_item(), treating
any errors as if the directory entry does not exists in the fs/subvolume
tree, which is obviously not correct, as we can get errors such as -EIO
when reading extent buffers while searching the fs/subvolume's tree.
Fix that by making inode_in_dir() return the errors and making its only
caller, add_inode_ref(), deal with returned errors as well.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 1b1499a817 upstream.
The nci_core_conn_close_rsp_packet() function will release the conn_info
with given conn_id. However, it needs to set the rf_conn_info to NULL to
prevent other routines like nci_rf_intf_activated_ntf_packet() to trigger
the UAF.
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Lin Ma <linma@zju.edu.cn>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 496c5fe25c upstream.
In isa206_idle_insn_mayloss() we store various registers into the stack
red zone, which is allowed.
However inside the IDLE_STATE_ENTER_SEQ_NORET macro we save r2 again,
to 0(r1), which corrupts the stack back chain.
We used to do the same in isa206_idle_insn_mayloss() itself, but we
fixed that in 73287caa92 ("powerpc64/idle: Fix SP offsets when saving
GPRs"), however we missed that the macro also corrupts the back chain.
Corrupting the back chain is bad for debuggability but doesn't
necessarily cause a bug.
However we recently changed the stack handling in some KVM code, and it
now relies on the stack back chain being valid when it returns. The
corruption causes that code to return with r1 pointing somewhere in
kernel data, at some point LR is restored from the stack and we branch
to NULL or somewhere else invalid.
Only affects Power8 hosts running KVM guests, with dynamic_mt_modes
enabled (which it is by default).
The fixes tag below points to the commit that changed the KVM stack
handling, exposing this bug. The actual corruption of the back chain has
always existed since 948cf67c47 ("powerpc: Add NAP mode support on
Power7 in HV mode").
Fixes: 9b4416c509 ("KVM: PPC: Book3S HV: Fix stack handling in idle_kvm_start_guest()")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211020094826.3222052-1-mpe@ellerman.id.au
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit cdeb5d7d89 upstream.
We call idle_kvm_start_guest() from power7_offline() if the thread has
been requested to enter KVM. We pass it the SRR1 value that was returned
from power7_idle_insn() which tells us what sort of wakeup we're
processing.
Depending on the SRR1 value we pass in, the KVM code might enter the
guest, or it might return to us to do some host action if the wakeup
requires it.
If idle_kvm_start_guest() is able to handle the wakeup, and enter the
guest it is supposed to indicate that by returning a zero SRR1 value to
us.
That was the behaviour prior to commit 10d91611f4 ("powerpc/64s:
Reimplement book3s idle code in C"), however in that commit the
handling of SRR1 was reworked, and the zeroing behaviour was lost.
Returning from idle_kvm_start_guest() without zeroing the SRR1 value can
confuse the host offline code, causing the guest to crash and other
weirdness.
Fixes: 10d91611f4 ("powerpc/64s: Reimplement book3s idle code in C")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211015133929.832061-2-mpe@ellerman.id.au
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9b4416c509 upstream.
In commit 10d91611f4 ("powerpc/64s: Reimplement book3s idle code in
C") kvm_start_guest() became idle_kvm_start_guest(). The old code
allocated a stack frame on the emergency stack, but didn't use the
frame to store anything, and also didn't store anything in its caller's
frame.
idle_kvm_start_guest() on the other hand is written more like a normal C
function, it creates a frame on entry, and also stores CR/LR into its
callers frame (per the ABI). The problem is that there is no caller
frame on the emergency stack.
The emergency stack for a given CPU is allocated with:
paca_ptrs[i]->emergency_sp = alloc_stack(limit, i) + THREAD_SIZE;
So emergency_sp actually points to the first address above the emergency
stack allocation for a given CPU, we must not store above it without
first decrementing it to create a frame. This is different to the
regular kernel stack, paca->kstack, which is initialised to point at an
initial frame that is ready to use.
idle_kvm_start_guest() stores the backchain, CR and LR all of which
write outside the allocation for the emergency stack. It then creates a
stack frame and saves the non-volatile registers. Unfortunately the
frame it creates is not large enough to fit the non-volatiles, and so
the saving of the non-volatile registers also writes outside the
emergency stack allocation.
The end result is that we corrupt whatever is at 0-24 bytes, and 112-248
bytes above the emergency stack allocation.
In practice this has gone unnoticed because the memory immediately above
the emergency stack happens to be used for other stack allocations,
either another CPUs mc_emergency_sp or an IRQ stack. See the order of
calls to irqstack_early_init() and emergency_stack_init().
The low addresses of another stack are the top of that stack, and so are
only used if that stack is under extreme pressue, which essentially
never happens in practice - and if it did there's a high likelyhood we'd
crash due to that stack overflowing.
Still, we shouldn't be corrupting someone else's stack, and it is purely
luck that we aren't corrupting something else.
To fix it we save CR/LR into the caller's frame using the existing r1 on
entry, we then create a SWITCH_FRAME_SIZE frame (which has space for
pt_regs) on the emergency stack with the backchain pointing to the
existing stack, and then finally we switch to the new frame on the
emergency stack.
Fixes: 10d91611f4 ("powerpc/64s: Reimplement book3s idle code in C")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211015133929.832061-1-mpe@ellerman.id.au
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 73287caa92 upstream.
The idle entry/exit code saves/restores GPRs in the stack "red zone"
(Protected Zone according to PowerPC64 ELF ABI v2). However, the offset
used for the first GPR is incorrect and overwrites the back chain - the
Protected Zone actually starts below the current SP. In practice this is
probably not an issue, but it's still incorrect so fix it.
Also expand the comments to explain why using the stack "red zone"
instead of creating a new stackframe is appropriate here.
Signed-off-by: Christopher M. Riedl <cmr@codefail.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210206072342.5067-1-cmr@codefail.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
