This is a note to let you know that I've just added the patch titled
net: usb: ax88179_178a: avoid failed operations when device is
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
From aef05e349bfd81c95adb4489639413fadbb74a83 Mon Sep 17 00:00:00 2001
From: Jose Ignacio Tornos Martinez <jtornosm(a)redhat.com>
Date: Thu, 7 Dec 2023 18:50:07 +0100
Subject: net: usb: ax88179_178a: avoid failed operations when device is
disconnected
When the device is disconnected we get the following messages showing
failed operations:
Nov 28 20:22:11 localhost kernel: usb 2-3: USB disconnect, device number 2
Nov 28 20:22:11 localhost kernel: ax88179_178a 2-3:1.0 enp2s0u3: unregister 'ax88179_178a' usb-0000:02:00.0-3, ASIX AX88179 USB 3.0 Gigabit Ethernet
Nov 28 20:22:11 localhost kernel: ax88179_178a 2-3:1.0 enp2s0u3: Failed to read reg index 0x0002: -19
Nov 28 20:22:11 localhost kernel: ax88179_178a 2-3:1.0 enp2s0u3: Failed to write reg index 0x0002: -19
Nov 28 20:22:11 localhost kernel: ax88179_178a 2-3:1.0 enp2s0u3 (unregistered): Failed to write reg index 0x0002: -19
Nov 28 20:22:11 localhost kernel: ax88179_178a 2-3:1.0 enp2s0u3 (unregistered): Failed to write reg index 0x0001: -19
Nov 28 20:22:11 localhost kernel: ax88179_178a 2-3:1.0 enp2s0u3 (unregistered): Failed to write reg index 0x0002: -19
The reason is that although the device is detached, normal stop and
unbind operations are commanded from the driver. These operations are
not necessary in this situation, so avoid these logs when the device is
detached if the result of the operation is -ENODEV and if the new flag
informing about the disconnecting status is enabled.
cc: <stable(a)vger.kernel.org>
Fixes: e2ca90c276e1f ("ax88179_178a: ASIX AX88179_178A USB 3.0/2.0 to gigabit ethernet adapter driver")
Signed-off-by: Jose Ignacio Tornos Martinez <jtornosm(a)redhat.com>
Acked-by: Alan Stern <stern(a)rowland.harvard.edu>
Link: https://lore.kernel.org/r/20231207175007.263907-1-jtornosm@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
drivers/net/usb/ax88179_178a.c | 23 ++++++++++++++++++++---
1 file changed, 20 insertions(+), 3 deletions(-)
diff --git a/drivers/net/usb/ax88179_178a.c b/drivers/net/usb/ax88179_178a.c
index 4ea0e155bb0d..5a1bf42ce156 100644
--- a/drivers/net/usb/ax88179_178a.c
+++ b/drivers/net/usb/ax88179_178a.c
@@ -173,6 +173,7 @@ struct ax88179_data {
u8 in_pm;
u32 wol_supported;
u32 wolopts;
+ u8 disconnecting;
};
struct ax88179_int_data {
@@ -208,6 +209,7 @@ static int __ax88179_read_cmd(struct usbnet *dev, u8 cmd, u16 value, u16 index,
{
int ret;
int (*fn)(struct usbnet *, u8, u8, u16, u16, void *, u16);
+ struct ax88179_data *ax179_data = dev->driver_priv;
BUG_ON(!dev);
@@ -219,7 +221,7 @@ static int __ax88179_read_cmd(struct usbnet *dev, u8 cmd, u16 value, u16 index,
ret = fn(dev, cmd, USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
value, index, data, size);
- if (unlikely(ret < 0))
+ if (unlikely((ret < 0) && !(ret == -ENODEV && ax179_data->disconnecting)))
netdev_warn(dev->net, "Failed to read reg index 0x%04x: %d\n",
index, ret);
@@ -231,6 +233,7 @@ static int __ax88179_write_cmd(struct usbnet *dev, u8 cmd, u16 value, u16 index,
{
int ret;
int (*fn)(struct usbnet *, u8, u8, u16, u16, const void *, u16);
+ struct ax88179_data *ax179_data = dev->driver_priv;
BUG_ON(!dev);
@@ -242,7 +245,7 @@ static int __ax88179_write_cmd(struct usbnet *dev, u8 cmd, u16 value, u16 index,
ret = fn(dev, cmd, USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
value, index, data, size);
- if (unlikely(ret < 0))
+ if (unlikely((ret < 0) && !(ret == -ENODEV && ax179_data->disconnecting)))
netdev_warn(dev->net, "Failed to write reg index 0x%04x: %d\n",
index, ret);
@@ -492,6 +495,20 @@ static int ax88179_resume(struct usb_interface *intf)
return usbnet_resume(intf);
}
+static void ax88179_disconnect(struct usb_interface *intf)
+{
+ struct usbnet *dev = usb_get_intfdata(intf);
+ struct ax88179_data *ax179_data;
+
+ if (!dev)
+ return;
+
+ ax179_data = dev->driver_priv;
+ ax179_data->disconnecting = 1;
+
+ usbnet_disconnect(intf);
+}
+
static void
ax88179_get_wol(struct net_device *net, struct ethtool_wolinfo *wolinfo)
{
@@ -1906,7 +1923,7 @@ static struct usb_driver ax88179_178a_driver = {
.suspend = ax88179_suspend,
.resume = ax88179_resume,
.reset_resume = ax88179_resume,
- .disconnect = usbnet_disconnect,
+ .disconnect = ax88179_disconnect,
.supports_autosuspend = 1,
.disable_hub_initiated_lpm = 1,
};
--
2.43.0
This is a note to let you know that I've just added the patch titled
dt-bindings: nvmem: mxs-ocotp: Document fsl,ocotp
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
From a2a8aefecbd0f87d6127951cef33b3def8439057 Mon Sep 17 00:00:00 2001
From: Fabio Estevam <festevam(a)denx.de>
Date: Fri, 15 Dec 2023 11:13:57 +0000
Subject: dt-bindings: nvmem: mxs-ocotp: Document fsl,ocotp
Both imx23.dtsi and imx28.dtsi describe the OCOTP nodes in
the format:
compatible = "fsl,imx28-ocotp", "fsl,ocotp";
Document the "fsl,ocotp" entry to fix the following schema
warning:
efuse@8002c000: compatible: ['fsl,imx23-ocotp', 'fsl,ocotp'] is too long
from schema $id: http://devicetree.org/schemas/nvmem/mxs-ocotp.yaml#
Fixes: 2c504460f502 ("dt-bindings: nvmem: Convert MXS OCOTP to json-schema")
Cc: <Stable(a)vger.kernel.org>
Signed-off-by: Fabio Estevam <festevam(a)denx.de>
Acked-by: Conor Dooley <conor.dooley(a)microchip.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla(a)linaro.org>
Link: https://lore.kernel.org/r/20231215111358.316727-2-srinivas.kandagatla@linar…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
Documentation/devicetree/bindings/nvmem/mxs-ocotp.yaml | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/Documentation/devicetree/bindings/nvmem/mxs-ocotp.yaml b/Documentation/devicetree/bindings/nvmem/mxs-ocotp.yaml
index f43186f98607..d9287be89877 100644
--- a/Documentation/devicetree/bindings/nvmem/mxs-ocotp.yaml
+++ b/Documentation/devicetree/bindings/nvmem/mxs-ocotp.yaml
@@ -15,9 +15,11 @@ allOf:
properties:
compatible:
- enum:
- - fsl,imx23-ocotp
- - fsl,imx28-ocotp
+ items:
+ - enum:
+ - fsl,imx23-ocotp
+ - fsl,imx28-ocotp
+ - const: fsl,ocotp
reg:
maxItems: 1
@@ -35,7 +37,7 @@ unevaluatedProperties: false
examples:
- |
ocotp: efuse@8002c000 {
- compatible = "fsl,imx28-ocotp";
+ compatible = "fsl,imx28-ocotp", "fsl,ocotp";
#address-cells = <1>;
#size-cells = <1>;
reg = <0x8002c000 0x2000>;
--
2.43.0
In commit 8930a6c20791 ("scsi: core: add support for request batching")
blk-mq last flags was mapped to SCMD_LAST and used as an indicator to
send the batch for the drivers that implement it but the error handling
code was not updated.
scsi_send_eh_cmnd(...) is used to send error handling commands and
request sense. The problem is that request sense comes as a single
command that gets into the batch queue and times out. As result
device goes offline after several failed resets. This was observed
on virtio_scsi device resize operation.
[ 496.316946] sd 0:0:4:0: [sdd] tag#117 scsi_eh_0: requesting sense
[ 506.786356] sd 0:0:4:0: [sdd] tag#117 scsi_send_eh_cmnd timeleft: 0
[ 506.787981] sd 0:0:4:0: [sdd] tag#117 abort
To fix this always set SCMD_LAST flag in scsi_send_eh_cmnd and
scsi_reset_ioctl(...).
Fixes: 8930a6c20791 ("scsi: core: add support for request batching")
Signed-off-by: Alexander Atanasov <alexander.atanasov(a)virtuozzo.com>
---
drivers/scsi/scsi_error.c | 2 ++
1 file changed, 2 insertions(+)
v1->v2: fix it globally not only for virtio_scsi, as suggested by
Paolo Bonzini, to avoid reintroducing the same bug.
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index c67cdcdc3ba8..1223d34c04da 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -1152,6 +1152,7 @@ static enum scsi_disposition scsi_send_eh_cmnd(struct scsi_cmnd *scmd,
scsi_log_send(scmd);
scmd->submitter = SUBMITTED_BY_SCSI_ERROR_HANDLER;
+ scmd->flags |= SCMD_LAST;
/*
* Lock sdev->state_mutex to avoid that scsi_device_quiesce() can
@@ -2459,6 +2460,7 @@ scsi_ioctl_reset(struct scsi_device *dev, int __user *arg)
scsi_init_command(dev, scmd);
scmd->submitter = SUBMITTED_BY_SCSI_RESET_IOCTL;
+ scmd->flags |= SCMD_LAST;
memset(&scmd->sdb, 0, sizeof(scmd->sdb));
scmd->cmd_len = 0;
--
2.39.3
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 41a506ef71eb38d94fe133f565c87c3e06ccc072
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2023080735-masculine-twister-ba16@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..
Possible dependencies:
41a506ef71eb ("powerpc/ftrace: Create a dummy stackframe to fix stack unwind")
a5f04d1f2724 ("powerpc/ftrace: Regroup PPC64 specific operations in ftrace_mprofile.S")
228216716cb5 ("powerpc/ftrace: Refactor ftrace_{regs_}caller")
9bdb2eec3dde ("powerpc/ftrace: Don't use lmw/stmw in ftrace_regs_caller()")
76b372814b08 ("powerpc/ftrace: Style cleanup in ftrace_mprofile.S")
fc75f8733798 ("powerpc/ftrace: Have arch_ftrace_get_regs() return NULL unless FL_SAVE_REGS is set")
34d8dac807f0 ("powerpc/ftrace: Also save r1 in ftrace_caller()")
4ee83a2cfbc4 ("powerpc/ftrace: Remove ftrace_32.S")
41315494beed ("powerpc/ftrace: Prepare ftrace_64_mprofile.S for reuse by PPC32")
830213786c49 ("powerpc/ftrace: directly call of function graph tracer by ftrace caller")
0c81ed5ed438 ("powerpc/ftrace: Refactor ftrace_{en/dis}able_ftrace_graph_caller")
40b035efe288 ("powerpc/ftrace: Implement CONFIG_DYNAMIC_FTRACE_WITH_ARGS")
c75388a8ceff ("powerpc/ftrace: Prepare PPC64's ftrace_caller() for CONFIG_DYNAMIC_FTRACE_WITH_ARGS")
d95bf254be5f ("powerpc/ftrace: Prepare PPC32's ftrace_caller() for CONFIG_DYNAMIC_FTRACE_WITH_ARGS")
7bdb478c1d15 ("powerpc/ftrace: Simplify PPC32's return_to_handler()")
7875bc9b07cd ("powerpc/ftrace: Don't save again LR in ftrace_regs_caller() on PPC32")
c545b9f040f3 ("powerpc/inst: Define ppc_inst_t")
aebd1fb45c62 ("powerpc: flexible GPR range save/restore macros")
7dfbfb87c243 ("powerpc/ftrace: Activate HAVE_DYNAMIC_FTRACE_WITH_REGS on PPC32")
c93d4f6ecf4b ("powerpc/ftrace: Add module_trampoline_target() for PPC32")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 41a506ef71eb38d94fe133f565c87c3e06ccc072 Mon Sep 17 00:00:00 2001
From: Naveen N Rao <naveen(a)kernel.org>
Date: Wed, 21 Jun 2023 10:43:49 +0530
Subject: [PATCH] powerpc/ftrace: Create a dummy stackframe to fix stack unwind
With ppc64 -mprofile-kernel and ppc32 -pg, profiling instructions to
call into ftrace are emitted right at function entry. The instruction
sequence used is minimal to reduce overhead. Crucially, a stackframe is
not created for the function being traced. This breaks stack unwinding
since the function being traced does not have a stackframe for itself.
As such, it never shows up in the backtrace:
/sys/kernel/debug/tracing # echo 1 > /proc/sys/kernel/stack_tracer_enabled
/sys/kernel/debug/tracing # cat stack_trace
Depth Size Location (17 entries)
----- ---- --------
0) 4144 32 ftrace_call+0x4/0x44
1) 4112 432 get_page_from_freelist+0x26c/0x1ad0
2) 3680 496 __alloc_pages+0x290/0x1280
3) 3184 336 __folio_alloc+0x34/0x90
4) 2848 176 vma_alloc_folio+0xd8/0x540
5) 2672 272 __handle_mm_fault+0x700/0x1cc0
6) 2400 208 handle_mm_fault+0xf0/0x3f0
7) 2192 80 ___do_page_fault+0x3e4/0xbe0
8) 2112 160 do_page_fault+0x30/0xc0
9) 1952 256 data_access_common_virt+0x210/0x220
10) 1696 400 0xc00000000f16b100
11) 1296 384 load_elf_binary+0x804/0x1b80
12) 912 208 bprm_execve+0x2d8/0x7e0
13) 704 64 do_execveat_common+0x1d0/0x2f0
14) 640 160 sys_execve+0x54/0x70
15) 480 64 system_call_exception+0x138/0x350
16) 416 416 system_call_common+0x160/0x2c4
Fix this by having ftrace create a dummy stackframe for the function
being traced. With this, backtraces now capture the function being
traced:
/sys/kernel/debug/tracing # cat stack_trace
Depth Size Location (17 entries)
----- ---- --------
0) 3888 32 _raw_spin_trylock+0x8/0x70
1) 3856 576 get_page_from_freelist+0x26c/0x1ad0
2) 3280 64 __alloc_pages+0x290/0x1280
3) 3216 336 __folio_alloc+0x34/0x90
4) 2880 176 vma_alloc_folio+0xd8/0x540
5) 2704 416 __handle_mm_fault+0x700/0x1cc0
6) 2288 96 handle_mm_fault+0xf0/0x3f0
7) 2192 48 ___do_page_fault+0x3e4/0xbe0
8) 2144 192 do_page_fault+0x30/0xc0
9) 1952 608 data_access_common_virt+0x210/0x220
10) 1344 16 0xc0000000334bbb50
11) 1328 416 load_elf_binary+0x804/0x1b80
12) 912 64 bprm_execve+0x2d8/0x7e0
13) 848 176 do_execveat_common+0x1d0/0x2f0
14) 672 192 sys_execve+0x54/0x70
15) 480 64 system_call_exception+0x138/0x350
16) 416 416 system_call_common+0x160/0x2c4
This results in two additional stores in the ftrace entry code, but
produces reliable backtraces.
Fixes: 153086644fd1 ("powerpc/ftrace: Add support for -mprofile-kernel ftrace ABI")
Cc: stable(a)vger.kernel.org
Signed-off-by: Naveen N Rao <naveen(a)kernel.org>
Signed-off-by: Michael Ellerman <mpe(a)ellerman.id.au>
Link: https://msgid.link/20230621051349.759567-1-naveen@kernel.org
diff --git a/arch/powerpc/kernel/trace/ftrace_mprofile.S b/arch/powerpc/kernel/trace/ftrace_mprofile.S
index ffb1db386849..1f7d86de1538 100644
--- a/arch/powerpc/kernel/trace/ftrace_mprofile.S
+++ b/arch/powerpc/kernel/trace/ftrace_mprofile.S
@@ -33,6 +33,9 @@
* and then arrange for the ftrace function to be called.
*/
.macro ftrace_regs_entry allregs
+ /* Create a minimal stack frame for representing B */
+ PPC_STLU r1, -STACK_FRAME_MIN_SIZE(r1)
+
/* Create our stack frame + pt_regs */
PPC_STLU r1,-SWITCH_FRAME_SIZE(r1)
@@ -42,7 +45,7 @@
#ifdef CONFIG_PPC64
/* Save the original return address in A's stack frame */
- std r0, LRSAVE+SWITCH_FRAME_SIZE(r1)
+ std r0, LRSAVE+SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE(r1)
/* Ok to continue? */
lbz r3, PACA_FTRACE_ENABLED(r13)
cmpdi r3, 0
@@ -77,6 +80,8 @@
mflr r7
/* Save it as pt_regs->nip */
PPC_STL r7, _NIP(r1)
+ /* Also save it in B's stackframe header for proper unwind */
+ PPC_STL r7, LRSAVE+SWITCH_FRAME_SIZE(r1)
/* Save the read LR in pt_regs->link */
PPC_STL r0, _LINK(r1)
@@ -142,7 +147,7 @@
#endif
/* Pop our stack frame */
- addi r1, r1, SWITCH_FRAME_SIZE
+ addi r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE
#ifdef CONFIG_LIVEPATCH_64
/* Based on the cmpd above, if the NIP was altered handle livepatch */
The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x 41a506ef71eb38d94fe133f565c87c3e06ccc072
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2023080737-guileless-magazine-d8dc@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
41a506ef71eb ("powerpc/ftrace: Create a dummy stackframe to fix stack unwind")
a5f04d1f2724 ("powerpc/ftrace: Regroup PPC64 specific operations in ftrace_mprofile.S")
228216716cb5 ("powerpc/ftrace: Refactor ftrace_{regs_}caller")
9bdb2eec3dde ("powerpc/ftrace: Don't use lmw/stmw in ftrace_regs_caller()")
76b372814b08 ("powerpc/ftrace: Style cleanup in ftrace_mprofile.S")
fc75f8733798 ("powerpc/ftrace: Have arch_ftrace_get_regs() return NULL unless FL_SAVE_REGS is set")
34d8dac807f0 ("powerpc/ftrace: Also save r1 in ftrace_caller()")
4ee83a2cfbc4 ("powerpc/ftrace: Remove ftrace_32.S")
41315494beed ("powerpc/ftrace: Prepare ftrace_64_mprofile.S for reuse by PPC32")
830213786c49 ("powerpc/ftrace: directly call of function graph tracer by ftrace caller")
0c81ed5ed438 ("powerpc/ftrace: Refactor ftrace_{en/dis}able_ftrace_graph_caller")
40b035efe288 ("powerpc/ftrace: Implement CONFIG_DYNAMIC_FTRACE_WITH_ARGS")
c75388a8ceff ("powerpc/ftrace: Prepare PPC64's ftrace_caller() for CONFIG_DYNAMIC_FTRACE_WITH_ARGS")
d95bf254be5f ("powerpc/ftrace: Prepare PPC32's ftrace_caller() for CONFIG_DYNAMIC_FTRACE_WITH_ARGS")
7bdb478c1d15 ("powerpc/ftrace: Simplify PPC32's return_to_handler()")
7875bc9b07cd ("powerpc/ftrace: Don't save again LR in ftrace_regs_caller() on PPC32")
c545b9f040f3 ("powerpc/inst: Define ppc_inst_t")
aebd1fb45c62 ("powerpc: flexible GPR range save/restore macros")
7dfbfb87c243 ("powerpc/ftrace: Activate HAVE_DYNAMIC_FTRACE_WITH_REGS on PPC32")
c93d4f6ecf4b ("powerpc/ftrace: Add module_trampoline_target() for PPC32")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 41a506ef71eb38d94fe133f565c87c3e06ccc072 Mon Sep 17 00:00:00 2001
From: Naveen N Rao <naveen(a)kernel.org>
Date: Wed, 21 Jun 2023 10:43:49 +0530
Subject: [PATCH] powerpc/ftrace: Create a dummy stackframe to fix stack unwind
With ppc64 -mprofile-kernel and ppc32 -pg, profiling instructions to
call into ftrace are emitted right at function entry. The instruction
sequence used is minimal to reduce overhead. Crucially, a stackframe is
not created for the function being traced. This breaks stack unwinding
since the function being traced does not have a stackframe for itself.
As such, it never shows up in the backtrace:
/sys/kernel/debug/tracing # echo 1 > /proc/sys/kernel/stack_tracer_enabled
/sys/kernel/debug/tracing # cat stack_trace
Depth Size Location (17 entries)
----- ---- --------
0) 4144 32 ftrace_call+0x4/0x44
1) 4112 432 get_page_from_freelist+0x26c/0x1ad0
2) 3680 496 __alloc_pages+0x290/0x1280
3) 3184 336 __folio_alloc+0x34/0x90
4) 2848 176 vma_alloc_folio+0xd8/0x540
5) 2672 272 __handle_mm_fault+0x700/0x1cc0
6) 2400 208 handle_mm_fault+0xf0/0x3f0
7) 2192 80 ___do_page_fault+0x3e4/0xbe0
8) 2112 160 do_page_fault+0x30/0xc0
9) 1952 256 data_access_common_virt+0x210/0x220
10) 1696 400 0xc00000000f16b100
11) 1296 384 load_elf_binary+0x804/0x1b80
12) 912 208 bprm_execve+0x2d8/0x7e0
13) 704 64 do_execveat_common+0x1d0/0x2f0
14) 640 160 sys_execve+0x54/0x70
15) 480 64 system_call_exception+0x138/0x350
16) 416 416 system_call_common+0x160/0x2c4
Fix this by having ftrace create a dummy stackframe for the function
being traced. With this, backtraces now capture the function being
traced:
/sys/kernel/debug/tracing # cat stack_trace
Depth Size Location (17 entries)
----- ---- --------
0) 3888 32 _raw_spin_trylock+0x8/0x70
1) 3856 576 get_page_from_freelist+0x26c/0x1ad0
2) 3280 64 __alloc_pages+0x290/0x1280
3) 3216 336 __folio_alloc+0x34/0x90
4) 2880 176 vma_alloc_folio+0xd8/0x540
5) 2704 416 __handle_mm_fault+0x700/0x1cc0
6) 2288 96 handle_mm_fault+0xf0/0x3f0
7) 2192 48 ___do_page_fault+0x3e4/0xbe0
8) 2144 192 do_page_fault+0x30/0xc0
9) 1952 608 data_access_common_virt+0x210/0x220
10) 1344 16 0xc0000000334bbb50
11) 1328 416 load_elf_binary+0x804/0x1b80
12) 912 64 bprm_execve+0x2d8/0x7e0
13) 848 176 do_execveat_common+0x1d0/0x2f0
14) 672 192 sys_execve+0x54/0x70
15) 480 64 system_call_exception+0x138/0x350
16) 416 416 system_call_common+0x160/0x2c4
This results in two additional stores in the ftrace entry code, but
produces reliable backtraces.
Fixes: 153086644fd1 ("powerpc/ftrace: Add support for -mprofile-kernel ftrace ABI")
Cc: stable(a)vger.kernel.org
Signed-off-by: Naveen N Rao <naveen(a)kernel.org>
Signed-off-by: Michael Ellerman <mpe(a)ellerman.id.au>
Link: https://msgid.link/20230621051349.759567-1-naveen@kernel.org
diff --git a/arch/powerpc/kernel/trace/ftrace_mprofile.S b/arch/powerpc/kernel/trace/ftrace_mprofile.S
index ffb1db386849..1f7d86de1538 100644
--- a/arch/powerpc/kernel/trace/ftrace_mprofile.S
+++ b/arch/powerpc/kernel/trace/ftrace_mprofile.S
@@ -33,6 +33,9 @@
* and then arrange for the ftrace function to be called.
*/
.macro ftrace_regs_entry allregs
+ /* Create a minimal stack frame for representing B */
+ PPC_STLU r1, -STACK_FRAME_MIN_SIZE(r1)
+
/* Create our stack frame + pt_regs */
PPC_STLU r1,-SWITCH_FRAME_SIZE(r1)
@@ -42,7 +45,7 @@
#ifdef CONFIG_PPC64
/* Save the original return address in A's stack frame */
- std r0, LRSAVE+SWITCH_FRAME_SIZE(r1)
+ std r0, LRSAVE+SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE(r1)
/* Ok to continue? */
lbz r3, PACA_FTRACE_ENABLED(r13)
cmpdi r3, 0
@@ -77,6 +80,8 @@
mflr r7
/* Save it as pt_regs->nip */
PPC_STL r7, _NIP(r1)
+ /* Also save it in B's stackframe header for proper unwind */
+ PPC_STL r7, LRSAVE+SWITCH_FRAME_SIZE(r1)
/* Save the read LR in pt_regs->link */
PPC_STL r0, _LINK(r1)
@@ -142,7 +147,7 @@
#endif
/* Pop our stack frame */
- addi r1, r1, SWITCH_FRAME_SIZE
+ addi r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE
#ifdef CONFIG_LIVEPATCH_64
/* Based on the cmpd above, if the NIP was altered handle livepatch */
The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y
git checkout FETCH_HEAD
git cherry-pick -x 41a506ef71eb38d94fe133f565c87c3e06ccc072
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2023080739-bonehead-overexert-ce34@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..
Possible dependencies:
41a506ef71eb ("powerpc/ftrace: Create a dummy stackframe to fix stack unwind")
a5f04d1f2724 ("powerpc/ftrace: Regroup PPC64 specific operations in ftrace_mprofile.S")
228216716cb5 ("powerpc/ftrace: Refactor ftrace_{regs_}caller")
9bdb2eec3dde ("powerpc/ftrace: Don't use lmw/stmw in ftrace_regs_caller()")
76b372814b08 ("powerpc/ftrace: Style cleanup in ftrace_mprofile.S")
fc75f8733798 ("powerpc/ftrace: Have arch_ftrace_get_regs() return NULL unless FL_SAVE_REGS is set")
34d8dac807f0 ("powerpc/ftrace: Also save r1 in ftrace_caller()")
4ee83a2cfbc4 ("powerpc/ftrace: Remove ftrace_32.S")
41315494beed ("powerpc/ftrace: Prepare ftrace_64_mprofile.S for reuse by PPC32")
830213786c49 ("powerpc/ftrace: directly call of function graph tracer by ftrace caller")
0c81ed5ed438 ("powerpc/ftrace: Refactor ftrace_{en/dis}able_ftrace_graph_caller")
40b035efe288 ("powerpc/ftrace: Implement CONFIG_DYNAMIC_FTRACE_WITH_ARGS")
c75388a8ceff ("powerpc/ftrace: Prepare PPC64's ftrace_caller() for CONFIG_DYNAMIC_FTRACE_WITH_ARGS")
d95bf254be5f ("powerpc/ftrace: Prepare PPC32's ftrace_caller() for CONFIG_DYNAMIC_FTRACE_WITH_ARGS")
7bdb478c1d15 ("powerpc/ftrace: Simplify PPC32's return_to_handler()")
7875bc9b07cd ("powerpc/ftrace: Don't save again LR in ftrace_regs_caller() on PPC32")
c545b9f040f3 ("powerpc/inst: Define ppc_inst_t")
aebd1fb45c62 ("powerpc: flexible GPR range save/restore macros")
7dfbfb87c243 ("powerpc/ftrace: Activate HAVE_DYNAMIC_FTRACE_WITH_REGS on PPC32")
c93d4f6ecf4b ("powerpc/ftrace: Add module_trampoline_target() for PPC32")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 41a506ef71eb38d94fe133f565c87c3e06ccc072 Mon Sep 17 00:00:00 2001
From: Naveen N Rao <naveen(a)kernel.org>
Date: Wed, 21 Jun 2023 10:43:49 +0530
Subject: [PATCH] powerpc/ftrace: Create a dummy stackframe to fix stack unwind
With ppc64 -mprofile-kernel and ppc32 -pg, profiling instructions to
call into ftrace are emitted right at function entry. The instruction
sequence used is minimal to reduce overhead. Crucially, a stackframe is
not created for the function being traced. This breaks stack unwinding
since the function being traced does not have a stackframe for itself.
As such, it never shows up in the backtrace:
/sys/kernel/debug/tracing # echo 1 > /proc/sys/kernel/stack_tracer_enabled
/sys/kernel/debug/tracing # cat stack_trace
Depth Size Location (17 entries)
----- ---- --------
0) 4144 32 ftrace_call+0x4/0x44
1) 4112 432 get_page_from_freelist+0x26c/0x1ad0
2) 3680 496 __alloc_pages+0x290/0x1280
3) 3184 336 __folio_alloc+0x34/0x90
4) 2848 176 vma_alloc_folio+0xd8/0x540
5) 2672 272 __handle_mm_fault+0x700/0x1cc0
6) 2400 208 handle_mm_fault+0xf0/0x3f0
7) 2192 80 ___do_page_fault+0x3e4/0xbe0
8) 2112 160 do_page_fault+0x30/0xc0
9) 1952 256 data_access_common_virt+0x210/0x220
10) 1696 400 0xc00000000f16b100
11) 1296 384 load_elf_binary+0x804/0x1b80
12) 912 208 bprm_execve+0x2d8/0x7e0
13) 704 64 do_execveat_common+0x1d0/0x2f0
14) 640 160 sys_execve+0x54/0x70
15) 480 64 system_call_exception+0x138/0x350
16) 416 416 system_call_common+0x160/0x2c4
Fix this by having ftrace create a dummy stackframe for the function
being traced. With this, backtraces now capture the function being
traced:
/sys/kernel/debug/tracing # cat stack_trace
Depth Size Location (17 entries)
----- ---- --------
0) 3888 32 _raw_spin_trylock+0x8/0x70
1) 3856 576 get_page_from_freelist+0x26c/0x1ad0
2) 3280 64 __alloc_pages+0x290/0x1280
3) 3216 336 __folio_alloc+0x34/0x90
4) 2880 176 vma_alloc_folio+0xd8/0x540
5) 2704 416 __handle_mm_fault+0x700/0x1cc0
6) 2288 96 handle_mm_fault+0xf0/0x3f0
7) 2192 48 ___do_page_fault+0x3e4/0xbe0
8) 2144 192 do_page_fault+0x30/0xc0
9) 1952 608 data_access_common_virt+0x210/0x220
10) 1344 16 0xc0000000334bbb50
11) 1328 416 load_elf_binary+0x804/0x1b80
12) 912 64 bprm_execve+0x2d8/0x7e0
13) 848 176 do_execveat_common+0x1d0/0x2f0
14) 672 192 sys_execve+0x54/0x70
15) 480 64 system_call_exception+0x138/0x350
16) 416 416 system_call_common+0x160/0x2c4
This results in two additional stores in the ftrace entry code, but
produces reliable backtraces.
Fixes: 153086644fd1 ("powerpc/ftrace: Add support for -mprofile-kernel ftrace ABI")
Cc: stable(a)vger.kernel.org
Signed-off-by: Naveen N Rao <naveen(a)kernel.org>
Signed-off-by: Michael Ellerman <mpe(a)ellerman.id.au>
Link: https://msgid.link/20230621051349.759567-1-naveen@kernel.org
diff --git a/arch/powerpc/kernel/trace/ftrace_mprofile.S b/arch/powerpc/kernel/trace/ftrace_mprofile.S
index ffb1db386849..1f7d86de1538 100644
--- a/arch/powerpc/kernel/trace/ftrace_mprofile.S
+++ b/arch/powerpc/kernel/trace/ftrace_mprofile.S
@@ -33,6 +33,9 @@
* and then arrange for the ftrace function to be called.
*/
.macro ftrace_regs_entry allregs
+ /* Create a minimal stack frame for representing B */
+ PPC_STLU r1, -STACK_FRAME_MIN_SIZE(r1)
+
/* Create our stack frame + pt_regs */
PPC_STLU r1,-SWITCH_FRAME_SIZE(r1)
@@ -42,7 +45,7 @@
#ifdef CONFIG_PPC64
/* Save the original return address in A's stack frame */
- std r0, LRSAVE+SWITCH_FRAME_SIZE(r1)
+ std r0, LRSAVE+SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE(r1)
/* Ok to continue? */
lbz r3, PACA_FTRACE_ENABLED(r13)
cmpdi r3, 0
@@ -77,6 +80,8 @@
mflr r7
/* Save it as pt_regs->nip */
PPC_STL r7, _NIP(r1)
+ /* Also save it in B's stackframe header for proper unwind */
+ PPC_STL r7, LRSAVE+SWITCH_FRAME_SIZE(r1)
/* Save the read LR in pt_regs->link */
PPC_STL r0, _LINK(r1)
@@ -142,7 +147,7 @@
#endif
/* Pop our stack frame */
- addi r1, r1, SWITCH_FRAME_SIZE
+ addi r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE
#ifdef CONFIG_LIVEPATCH_64
/* Based on the cmpd above, if the NIP was altered handle livepatch */