nvmet-trace: avoid dereferencing pointer too early

[ Upstream commit 0e716cec6fb11a14c220ee17c404b67962e902f7 ]

The first command issued from the host to the target is the fabrics
connect command.

nvmet-trace: avoid dereferencing pointer too early

[ Upstream commit 0e716cec6fb11a14c220ee17c404b67962e902f7 ]

The first command issued from the host to the target is the fabrics
connect command. At this point, neither the target queue nor the
controller have been allocated. But we already try to trace this command
in nvmet_req_init.

Reported by KASAN.

Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Daniel Wagner <dwagner@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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nvme: trace: avoid memcpy overflow warning

[ Upstream commit a7de1dea76cd6a3707707af4ea2f8bc3cdeaeb11 ]

A previous patch introduced a struct_group() in nvme_common_command to help
stringop fortific

nvme: trace: avoid memcpy overflow warning

[ Upstream commit a7de1dea76cd6a3707707af4ea2f8bc3cdeaeb11 ]

A previous patch introduced a struct_group() in nvme_common_command to help
stringop fortification figure out the length of the fields, but one function
is not currently using them:

In file included from drivers/nvme/target/core.c:7:
In file included from include/linux/string.h:254:
include/linux/fortify-string.h:592:4: error: call to '__read_overflow2_field' declared with 'warning' attribute: detected read beyond size of field (2nd parameter); maybe use struct_group()? [-Werror,-Wattribute-warning]
__read_overflow2_field(q_size_field, size);
^

Change this one to use the correct field name to avoid the warning.

Fixes: 5c629dc9609dc ("nvme: use struct group for generic command dwords")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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nvmet: re-fix tracing strncpy() warning

[ Upstream commit 4ee7ffeb4ce50c80bc4504db6f39b25a2df6bcf4 ]

An earlier patch had tried to address a warning about a string copy with
missing zero terminatio

nvmet: re-fix tracing strncpy() warning

[ Upstream commit 4ee7ffeb4ce50c80bc4504db6f39b25a2df6bcf4 ]

An earlier patch had tried to address a warning about a string copy with
missing zero termination:

drivers/nvme/target/trace.h:52:3: warning: ‘strncpy’ specified bound 32 equals destination size [-Wstringop-truncation]

The new version causes a different warning with some compiler versions, notably
gcc-9 and gcc-10, and also misses the zero padding that was apparently done
intentionally in the original code:

drivers/nvme/target/trace.h:56:2: error: 'strncpy' specified bound depends on the length of the source argument [-Werror=stringop-overflow=]

Change it to use strscpy_pad() with the original length, which will give
a properly padded and zero-terminated string as well as avoiding the warning.

Fixes: d86481e924a7 ("nvmet: use min of device_path and disk len")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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nvmet: use min of device_path and disk len

In function __assign_req_name() instead of using the DEVICE_NAME_LEN in
strncpy() use min of DISK_NAME_LEN and strlen(req->ns->device_path).

This is neede

nvmet: use min of device_path and disk len

In function __assign_req_name() instead of using the DEVICE_NAME_LEN in
strncpy() use min of DISK_NAME_LEN and strlen(req->ns->device_path).

This is needed to turn off the following warnings:-

In file included from drivers/nvme/target/core.c:14:
In function ‘__assign_req_name’,
inlined from ‘trace_event_raw_event_nvmet_req_init’ at drivers/nvme/target/./trace.h:58:1:
drivers/nvme/target/trace.h:52:3: warning: ‘strncpy’ specified bound 32 equals destination size [-Wstringop-truncation]
strncpy(name, req->ns->device_path, DISK_NAME_LEN);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function ‘__assign_req_name’,
inlined from ‘perf_trace_nvmet_req_complete’ at drivers/nvme/target/./trace.h:100:1:
drivers/nvme/target/trace.h:52:3: warning: ‘strncpy’ specified bound 32 equals destination size [-Wstringop-truncation]
strncpy(name, req->ns->device_path, DISK_NAME_LEN);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function ‘__assign_req_name’,
inlined from ‘perf_trace_nvmet_req_init’ at drivers/nvme/target/./trace.h:58:1:
drivers/nvme/target/trace.h:52:3: warning: ‘strncpy’ specified bound 32 equals destination size [-Wstringop-truncation]
strncpy(name, req->ns->device_path, DISK_NAME_LEN);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function ‘__assign_req_name’,
inlined from ‘trace_event_raw_event_nvmet_req_complete’ at drivers/nvme/target/./trace.h:100:1:
drivers/nvme/target/trace.h:52:3: warning: ‘strncpy’ specified bound 32 equals destination size [-Wstringop-truncation]
strncpy(name, req->ns->device_path, DISK_NAME_LEN);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

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nvmet: fix a NULL pointer dereference when tracing the flush command

When target side trace in turned on and flush command is issued from the
host it results in the following Oops.

[ 856.789724] B

nvmet: fix a NULL pointer dereference when tracing the flush command

When target side trace in turned on and flush command is issued from the
host it results in the following Oops.

[ 856.789724] BUG: kernel NULL pointer dereference, address: 0000000000000068
[ 856.790686] #PF: supervisor read access in kernel mode
[ 856.791262] #PF: error_code(0x0000) - not-present page
[ 856.791863] PGD 6d7110067 P4D 6d7110067 PUD 66f0ad067 PMD 0
[ 856.792527] Oops: 0000 [#1] SMP NOPTI
[ 856.792950] CPU: 15 PID: 7034 Comm: nvme Tainted: G OE 5.9.0nvme-5.9+ #71
[ 856.793790] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e3214
[ 856.794956] RIP: 0010:trace_event_raw_event_nvmet_req_init+0x13e/0x170 [nvmet]
[ 856.795734] Code: 41 5c 41 5d c3 31 d2 31 f6 e8 4e 9b b8 e0 e9 0e ff ff ff 49 8b 55 00 48 8b 38 8b 0
[ 856.797740] RSP: 0018:ffffc90001be3a60 EFLAGS: 00010246
[ 856.798375] RAX: 0000000000000000 RBX: ffff8887e7d2c01c RCX: 0000000000000000
[ 856.799234] RDX: 0000000000000020 RSI: 0000000057e70ea2 RDI: ffff8887e7d2c034
[ 856.800088] RBP: ffff88869f710578 R08: ffff888807500d40 R09: 00000000fffffffe
[ 856.800951] R10: 0000000064c66670 R11: 00000000ef955201 R12: ffff8887e7d2c034
[ 856.801807] R13: ffff88869f7105c8 R14: 0000000000000040 R15: ffff88869f710440
[ 856.802667] FS: 00007f6a22bd8780(0000) GS:ffff888813a00000(0000) knlGS:0000000000000000
[ 856.803635] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 856.804367] CR2: 0000000000000068 CR3: 00000006d73e0000 CR4: 00000000003506e0
[ 856.805283] Call Trace:
[ 856.805613] nvmet_req_init+0x27c/0x480 [nvmet]
[ 856.806200] nvme_loop_queue_rq+0xcb/0x1d0 [nvme_loop]
[ 856.806862] blk_mq_dispatch_rq_list+0x123/0x7b0
[ 856.807459] ? kvm_sched_clock_read+0x14/0x30
[ 856.808025] __blk_mq_sched_dispatch_requests+0xc7/0x170
[ 856.808708] blk_mq_sched_dispatch_requests+0x30/0x60
[ 856.809372] __blk_mq_run_hw_queue+0x70/0x100
[ 856.809935] __blk_mq_delay_run_hw_queue+0x156/0x170
[ 856.810574] blk_mq_run_hw_queue+0x86/0xe0
[ 856.811104] blk_mq_sched_insert_request+0xef/0x160
[ 856.811733] blk_execute_rq+0x69/0xc0
[ 856.812212] ? blk_mq_rq_ctx_init+0xd0/0x230
[ 856.812784] nvme_execute_passthru_rq+0x57/0x130 [nvme_core]
[ 856.813461] nvme_submit_user_cmd+0xeb/0x300 [nvme_core]
[ 856.814099] nvme_user_cmd.isra.82+0x11e/0x1a0 [nvme_core]
[ 856.814752] blkdev_ioctl+0x1dc/0x2c0
[ 856.815197] block_ioctl+0x3f/0x50
[ 856.815606] __x64_sys_ioctl+0x84/0xc0
[ 856.816074] do_syscall_64+0x33/0x40
[ 856.816533] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 856.817168] RIP: 0033:0x7f6a222ed107
[ 856.817617] Code: 44 00 00 48 8b 05 81 cd 2c 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 8
[ 856.819901] RSP: 002b:00007ffca848f058 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
[ 856.820846] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f6a222ed107
[ 856.821726] RDX: 00007ffca848f060 RSI: 00000000c0484e43 RDI: 0000000000000003
[ 856.822603] RBP: 0000000000000003 R08: 000000000000003f R09: 0000000000000005
[ 856.823478] R10: 00007ffca848ece0 R11: 0000000000000202 R12: 00007ffca84912d3
[ 856.824359] R13: 00007ffca848f4d0 R14: 0000000000000002 R15: 000000000067e900
[ 856.825236] Modules linked in: nvme_loop(OE) nvmet(OE) nvme_fabrics(OE) null_blk nvme(OE) nvme_corel

Move the nvmet_req_init() tracepoint after we parse the command in
nvmet_req_init() so that we can get rid of the duplicate
nvmet_find_namespace() call.
Rename __assign_disk_name() -> __assign_req_name(). Now that we call
tracepoint after parsing the command simplify the newly added
__assign_req_name() which fixes this bug.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

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nvmet: add async event tracing support

This adds a new tracepoint for the target to trace async event. This is
helpful in debugging and comparing host and target side async events
especially when ho

nvmet: add async event tracing support

This adds a new tracepoint for the target to trace async event. This is
helpful in debugging and comparing host and target side async events
especially when host is connected to different targets on different
machines and now that we rely on userspace components to generate AEN. 

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

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nvmet: introduce target-side trace

This patch introduces target-side request tracing. As Christoph
suggested, the trace would not be in a core or module to avoid
disadvantages like cache miss:
ht

nvmet: introduce target-side trace

This patch introduces target-side request tracing. As Christoph
suggested, the trace would not be in a core or module to avoid
disadvantages like cache miss:
http://lists.infradead.org/pipermail/linux-nvme/2019-June/024721.html

The target-side trace code is entirely based on the Johannes's trace code
from the host side. It has lots of codes duplicated, but it would be
better than having advantages mentioned above.

It also traces not only fabrics commands, but also nvme normal commands.
Once the codes to be shared gets bigger, then we can make it common as
suggsted.

This also removed the create_sq and create_cq trace parsing functions
because it will be done by the connect fabrics command.

Example:
echo 1 > /sys/kernel/debug/tracing/event/nvmet/nvmet_req_init/enable
echo 1 > /sys/kernel/debug/tracing/event/nvmet/nvmet_req_complete/enable
cat /sys/kernel/debug/tracing/trace

Signed-off-by: Minwoo Im <minwoo.im.dev@gmail.com>
[hch: fixed the symbol namespace and a an endianess conversion]
Signed-off-by: Christoph Hellwig <hch@lst.de>

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