linux.git/net/9p, branch master Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git 9p: fix slab cache name creation for real 2024-10-21T22:41:29+00:00 Linus Torvalds torvalds@linux-foundation.org 2024-10-21T18:57:38+00:00 a360f311f57a36e96d88fa8086b749159714dcd2 This was attempted by using the dev_name in the slab cache name, but as Omar Sandoval pointed out, that can be an arbitrary string, eg something like "/dev/root". Which in turn trips verify_dirent_name(), which fails if a filename contains a slash. So just make it use a sequence counter, and make it an atomic_t to avoid any possible races or locking issues. Reported-and-tested-by: Omar Sandoval <osandov@fb.com> Link: https://lore.kernel.org/all/ZxafcO8KWMlXaeWE@telecaster.dhcp.thefacebook.com/ Fixes: 79efebae4afc ("9p: Avoid creating multiple slab caches with the same name") Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dominique Martinet <asmadeus@codewreck.org> Cc: Thorsten Leemhuis <regressions@leemhuis.info> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
This was attempted by using the dev_name in the slab cache name, but as
Omar Sandoval pointed out, that can be an arbitrary string, eg something
like "/dev/root".  Which in turn trips verify_dirent_name(), which fails
if a filename contains a slash.

So just make it use a sequence counter, and make it an atomic_t to avoid
any possible races or locking issues.

Reported-and-tested-by: Omar Sandoval <osandov@fb.com>
Link: https://lore.kernel.org/all/ZxafcO8KWMlXaeWE@telecaster.dhcp.thefacebook.com/
Fixes: 79efebae4afc ("9p: Avoid creating multiple slab caches with the same name")
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dominique Martinet <asmadeus@codewreck.org>
Cc: Thorsten Leemhuis <regressions@leemhuis.info>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge tag '9p-for-6.12-rc4' of https://github.com/martinetd/linux 2024-10-19T15:44:10+00:00 Linus Torvalds torvalds@linux-foundation.org 2024-10-19T15:44:10+00:00 9197b73fd7bb263084a95d1c578b7ee0ad54dfb3 Pull 9p fixes from Dominique Martinet: "Mashed-up update that I sat on too long: - fix for multiple slabs created with the same name - enable multipage folios - theorical fix to also look for opened fids by inode if none was found by dentry" [ Enabling multi-page folios should have been done during the merge window, but it's a one-liner, and the actual meat of the enablement is in netfs and already in use for other filesystems... - Linus ] * tag '9p-for-6.12-rc4' of https://github.com/martinetd/linux: 9p: Avoid creating multiple slab caches with the same name 9p: Enable multipage folios 9p: v9fs_fid_find: also lookup by inode if not found dentry 
Pull 9p fixes from Dominique Martinet:
 "Mashed-up update that I sat on too long:

   - fix for multiple slabs created with the same name

   - enable multipage folios

   - theorical fix to also look for opened fids by inode if none was
     found by dentry"

[ Enabling multi-page folios should have been done during the merge
  window, but it's a one-liner, and the actual meat of the enablement
  is in netfs and already in use for other filesystems...  - Linus ]

* tag '9p-for-6.12-rc4' of https://github.com/martinetd/linux:
  9p: Avoid creating multiple slab caches with the same name
  9p: Enable multipage folios
  9p: v9fs_fid_find: also lookup by inode if not found dentry
net/9p/usbg: Fix build error 2024-10-09T07:56:40+00:00 Jinjie Ruan ruanjinjie@huawei.com 2024-09-30T08:15:20+00:00 faa34159d08089036b6119c85e279fb36abb8bb5 When CONFIG_NET_9P_USBG=y but CONFIG_USB_LIBCOMPOSITE=m and CONFIG_CONFIGFS_FS=m, the following build error occurs: riscv64-unknown-linux-gnu-ld: net/9p/trans_usbg.o: in function `usb9pfs_free_func': trans_usbg.c:(.text+0x124): undefined reference to `usb_free_all_descriptors' riscv64-unknown-linux-gnu-ld: net/9p/trans_usbg.o: in function `usb9pfs_rx_complete': trans_usbg.c:(.text+0x2d8): undefined reference to `usb_interface_id' riscv64-unknown-linux-gnu-ld: trans_usbg.c:(.text+0x2f6): undefined reference to `usb_string_id' riscv64-unknown-linux-gnu-ld: net/9p/trans_usbg.o: in function `usb9pfs_func_bind': trans_usbg.c:(.text+0x31c): undefined reference to `usb_ep_autoconfig' riscv64-unknown-linux-gnu-ld: trans_usbg.c:(.text+0x336): undefined reference to `usb_ep_autoconfig' riscv64-unknown-linux-gnu-ld: trans_usbg.c:(.text+0x378): undefined reference to `usb_assign_descriptors' riscv64-unknown-linux-gnu-ld: net/9p/trans_usbg.o: in function `f_usb9pfs_opts_buflen_store': trans_usbg.c:(.text+0x49e): undefined reference to `usb_put_function_instance' riscv64-unknown-linux-gnu-ld: net/9p/trans_usbg.o: in function `usb9pfs_alloc_instance': trans_usbg.c:(.text+0x5fe): undefined reference to `config_group_init_type_name' riscv64-unknown-linux-gnu-ld: net/9p/trans_usbg.o: in function `usb9pfs_alloc': trans_usbg.c:(.text+0x7aa): undefined reference to `config_ep_by_speed' riscv64-unknown-linux-gnu-ld: trans_usbg.c:(.text+0x7ea): undefined reference to `config_ep_by_speed' riscv64-unknown-linux-gnu-ld: net/9p/trans_usbg.o: in function `usb9pfs_set_alt': trans_usbg.c:(.text+0x828): undefined reference to `alloc_ep_req' riscv64-unknown-linux-gnu-ld: net/9p/trans_usbg.o: in function `usb9pfs_modexit': trans_usbg.c:(.exit.text+0x10): undefined reference to `usb_function_unregister' riscv64-unknown-linux-gnu-ld: net/9p/trans_usbg.o: in function `usb9pfs_modinit': trans_usbg.c:(.init.text+0x1e): undefined reference to `usb_function_register' Select the config for NET_9P_USBG to fix it. Fixes: a3be076dc174 ("net/9p/usbg: Add new usb gadget function transport") Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Tested-by: Kexy Biscuit <kexybiscuit@aosc.io> Link: https://lore.kernel.org/r/20240930081520.2371424-1-ruanjinjie@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
When CONFIG_NET_9P_USBG=y but CONFIG_USB_LIBCOMPOSITE=m and
CONFIG_CONFIGFS_FS=m, the following build error occurs:

	riscv64-unknown-linux-gnu-ld: net/9p/trans_usbg.o: in function `usb9pfs_free_func':
	trans_usbg.c:(.text+0x124): undefined reference to `usb_free_all_descriptors'
	riscv64-unknown-linux-gnu-ld: net/9p/trans_usbg.o: in function `usb9pfs_rx_complete':
	trans_usbg.c:(.text+0x2d8): undefined reference to `usb_interface_id'
	riscv64-unknown-linux-gnu-ld: trans_usbg.c:(.text+0x2f6): undefined reference to `usb_string_id'
	riscv64-unknown-linux-gnu-ld: net/9p/trans_usbg.o: in function `usb9pfs_func_bind':
	trans_usbg.c:(.text+0x31c): undefined reference to `usb_ep_autoconfig'
	riscv64-unknown-linux-gnu-ld: trans_usbg.c:(.text+0x336): undefined reference to `usb_ep_autoconfig'
	riscv64-unknown-linux-gnu-ld: trans_usbg.c:(.text+0x378): undefined reference to `usb_assign_descriptors'
	riscv64-unknown-linux-gnu-ld: net/9p/trans_usbg.o: in function `f_usb9pfs_opts_buflen_store':
	trans_usbg.c:(.text+0x49e): undefined reference to `usb_put_function_instance'
	riscv64-unknown-linux-gnu-ld: net/9p/trans_usbg.o: in function `usb9pfs_alloc_instance':
	trans_usbg.c:(.text+0x5fe): undefined reference to `config_group_init_type_name'
	riscv64-unknown-linux-gnu-ld: net/9p/trans_usbg.o: in function `usb9pfs_alloc':
	trans_usbg.c:(.text+0x7aa): undefined reference to `config_ep_by_speed'
	riscv64-unknown-linux-gnu-ld: trans_usbg.c:(.text+0x7ea): undefined reference to `config_ep_by_speed'
	riscv64-unknown-linux-gnu-ld: net/9p/trans_usbg.o: in function `usb9pfs_set_alt':
	trans_usbg.c:(.text+0x828): undefined reference to `alloc_ep_req'
	riscv64-unknown-linux-gnu-ld: net/9p/trans_usbg.o: in function `usb9pfs_modexit':
	trans_usbg.c:(.exit.text+0x10): undefined reference to `usb_function_unregister'
	riscv64-unknown-linux-gnu-ld: net/9p/trans_usbg.o: in function `usb9pfs_modinit':
	trans_usbg.c:(.init.text+0x1e): undefined reference to `usb_function_register'

Select the config for NET_9P_USBG to fix it.

Fixes: a3be076dc174 ("net/9p/usbg: Add new usb gadget function transport")
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Tested-by: Kexy Biscuit <kexybiscuit@aosc.io>
Link: https://lore.kernel.org/r/20240930081520.2371424-1-ruanjinjie@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
9p: Avoid creating multiple slab caches with the same name 2024-09-22T20:51:27+00:00 Pedro Falcato pedro.falcato@gmail.com 2024-08-07T09:47:25+00:00 79efebae4afc2221fa814c3cae001bede66ab259 In the spirit of [1], avoid creating multiple slab caches with the same name. Instead, add the dev_name into the mix. [1]: https://lore.kernel.org/all/20240807090746.2146479-1-pedro.falcato@gmail.com/ Signed-off-by: Pedro Falcato <pedro.falcato@gmail.com> Reported-by: syzbot+3c5d43e97993e1fa612b@syzkaller.appspotmail.com Message-ID: <20240807094725.2193423-1-pedro.falcato@gmail.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org> 
In the spirit of [1], avoid creating multiple slab caches with the same
name. Instead, add the dev_name into the mix.

[1]: https://lore.kernel.org/all/20240807090746.2146479-1-pedro.falcato@gmail.com/

Signed-off-by: Pedro Falcato <pedro.falcato@gmail.com>
Reported-by: syzbot+3c5d43e97993e1fa612b@syzkaller.appspotmail.com
Message-ID: <20240807094725.2193423-1-pedro.falcato@gmail.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
net/9p/usbg: fix CONFIG_USB_GADGET dependency 2024-09-11T13:59:43+00:00 Arnd Bergmann arnd@arndb.de 2024-09-09T11:17:38+00:00 2193ede180dde21b7f866cc457eb9e13341e663b When USB gadget support is in a loadable module, 9pfs cannot link to it as a built-in driver: x86_64-linux-ld: vmlinux.o: in function `usb9pfs_free_func': trans_usbg.c:(.text+0x1070012): undefined reference to `usb_free_all_descriptors' x86_64-linux-ld: vmlinux.o: in function `disable_ep': trans_usbg.c:(.text+0x1070528): undefined reference to `usb_ep_disable' x86_64-linux-ld: vmlinux.o: in function `usb9pfs_func_unbind': trans_usbg.c:(.text+0x10705df): undefined reference to `usb_ep_free_request' x86_64-linux-ld: trans_usbg.c:(.text+0x107061f): undefined reference to `usb_ep_free_request' x86_64-linux-ld: vmlinux.o: in function `usb9pfs_func_bind': trans_usbg.c:(.text+0x107069f): undefined reference to `usb_interface_id' x86_64-linux-ld: trans_usbg.c:(.text+0x10706b5): undefined reference to `usb_string_id' Change the Kconfig dependency to only allow this to be enabled when it can successfully link and work. Fixes: a3be076dc174 ("net/9p/usbg: Add new usb gadget function transport") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Link: https://lore.kernel.org/r/20240909111745.248952-1-arnd@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
When USB gadget support is in a loadable module, 9pfs cannot
link to it as a built-in driver:

x86_64-linux-ld: vmlinux.o: in function `usb9pfs_free_func':
trans_usbg.c:(.text+0x1070012): undefined reference to `usb_free_all_descriptors'
x86_64-linux-ld: vmlinux.o: in function `disable_ep':
trans_usbg.c:(.text+0x1070528): undefined reference to `usb_ep_disable'
x86_64-linux-ld: vmlinux.o: in function `usb9pfs_func_unbind':
trans_usbg.c:(.text+0x10705df): undefined reference to `usb_ep_free_request'
x86_64-linux-ld: trans_usbg.c:(.text+0x107061f): undefined reference to `usb_ep_free_request'
x86_64-linux-ld: vmlinux.o: in function `usb9pfs_func_bind':
trans_usbg.c:(.text+0x107069f): undefined reference to `usb_interface_id'
x86_64-linux-ld: trans_usbg.c:(.text+0x10706b5): undefined reference to `usb_string_id'

Change the Kconfig dependency to only allow this to be enabled
when it can successfully link and work.

Fixes: a3be076dc174 ("net/9p/usbg: Add new usb gadget function transport")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20240909111745.248952-1-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/9p/usbg: Add new usb gadget function transport 2024-09-03T07:57:08+00:00 Michael Grzeschik m.grzeschik@pengutronix.de 2024-09-01T19:11:17+00:00 a3be076dc174d9022a71a12554feb4c97b5c4d5c Add the new gadget function for 9pfs transport. This function is defining an simple 9pfs transport interface that consists of one in and one out endpoint. The endpoints transmit and receive the 9pfs protocol payload when mounting a 9p filesystem over usb. Tested-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com> Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de> Link: https://lore.kernel.org/r/20240116-ml-topic-u9p-v12-2-9a27de5160e0@pengutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Add the new gadget function for 9pfs transport. This function is
defining an simple 9pfs transport interface that consists of one in and
one out endpoint. The endpoints transmit and receive the 9pfs protocol
payload when mounting a 9p filesystem over usb.

Tested-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Link: https://lore.kernel.org/r/20240116-ml-topic-u9p-v12-2-9a27de5160e0@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Merge tag '9p-for-6.10-rc2' of https://github.com/martinetd/linux 2024-05-29T16:25:15+00:00 Linus Torvalds torvalds@linux-foundation.org 2024-05-29T16:25:15+00:00 397a83ab978553ca2970ad1ccdbac0cdc732efd9 Pull 9p fixes from Dominique Martinet: "Two fixes headed to stable trees: - a trace event was dumping uninitialized values - a missing lock that was thought to have exclusive access, and it turned out not to" * tag '9p-for-6.10-rc2' of https://github.com/martinetd/linux: 9p: add missing locking around taking dentry fid list net/9p: fix uninit-value in p9_client_rpc() 
Pull 9p fixes from Dominique Martinet:
 "Two fixes headed to stable trees:

   - a trace event was dumping uninitialized values

   - a missing lock that was thought to have exclusive access, and it
     turned out not to"

* tag '9p-for-6.10-rc2' of https://github.com/martinetd/linux:
  9p: add missing locking around taking dentry fid list
  net/9p: fix uninit-value in p9_client_rpc()
Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost 2024-05-23T19:04:36+00:00 Linus Torvalds torvalds@linux-foundation.org 2024-05-23T19:04:36+00:00 2ef32ad2241340565c35baf77fc95053c84eeeb0 Pull virtio updates from Michael Tsirkin: "Several new features here: - virtio-net is finally supported in vduse - virtio (balloon and mem) interaction with suspend is improved - vhost-scsi now handles signals better/faster And fixes, cleanups all over the place" * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (48 commits) virtio-pci: Check if is_avq is NULL virtio: delete vq in vp_find_vqs_msix() when request_irq() fails MAINTAINERS: add Eugenio Pérez as reviewer vhost-vdpa: Remove usage of the deprecated ida_simple_xx() API vp_vdpa: don't allocate unused msix vectors sound: virtio: drop owner assignment fuse: virtio: drop owner assignment scsi: virtio: drop owner assignment rpmsg: virtio: drop owner assignment nvdimm: virtio_pmem: drop owner assignment wifi: mac80211_hwsim: drop owner assignment vsock/virtio: drop owner assignment net: 9p: virtio: drop owner assignment net: virtio: drop owner assignment net: caif: virtio: drop owner assignment misc: nsm: drop owner assignment iommu: virtio: drop owner assignment drm/virtio: drop owner assignment gpio: virtio: drop owner assignment firmware: arm_scmi: virtio: drop owner assignment ... 
Pull virtio updates from Michael Tsirkin:
 "Several new features here:

   - virtio-net is finally supported in vduse

   - virtio (balloon and mem) interaction with suspend is improved

   - vhost-scsi now handles signals better/faster

  And fixes, cleanups all over the place"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (48 commits)
  virtio-pci: Check if is_avq is NULL
  virtio: delete vq in vp_find_vqs_msix() when request_irq() fails
  MAINTAINERS: add Eugenio Pérez as reviewer
  vhost-vdpa: Remove usage of the deprecated ida_simple_xx() API
  vp_vdpa: don't allocate unused msix vectors
  sound: virtio: drop owner assignment
  fuse: virtio: drop owner assignment
  scsi: virtio: drop owner assignment
  rpmsg: virtio: drop owner assignment
  nvdimm: virtio_pmem: drop owner assignment
  wifi: mac80211_hwsim: drop owner assignment
  vsock/virtio: drop owner assignment
  net: 9p: virtio: drop owner assignment
  net: virtio: drop owner assignment
  net: caif: virtio: drop owner assignment
  misc: nsm: drop owner assignment
  iommu: virtio: drop owner assignment
  drm/virtio: drop owner assignment
  gpio: virtio: drop owner assignment
  firmware: arm_scmi: virtio: drop owner assignment
  ...
net: 9p: virtio: drop owner assignment 2024-05-22T12:31:17+00:00 Krzysztof Kozlowski krzysztof.kozlowski@linaro.org 2024-03-31T08:44:05+00:00 d26dd255ce44e325e163ff3ce53423d26911ad11 virtio core already sets the .owner, so driver does not need to. Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Message-Id: <20240331-module-owner-virtio-v2-18-98f04bfaf46a@linaro.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> 
virtio core already sets the .owner, so driver does not need to.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Message-Id: <20240331-module-owner-virtio-v2-18-98f04bfaf46a@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
net/9p: fix uninit-value in p9_client_rpc() 2024-05-21T12:27:28+00:00 Nikita Zhandarovich n.zhandarovich@fintech.ru 2024-04-08T14:10:39+00:00 25460d6f39024cc3b8241b14c7ccf0d6f11a736a Syzbot with the help of KMSAN reported the following error: BUG: KMSAN: uninit-value in trace_9p_client_res include/trace/events/9p.h:146 [inline] BUG: KMSAN: uninit-value in p9_client_rpc+0x1314/0x1340 net/9p/client.c:754 trace_9p_client_res include/trace/events/9p.h:146 [inline] p9_client_rpc+0x1314/0x1340 net/9p/client.c:754 p9_client_create+0x1551/0x1ff0 net/9p/client.c:1031 v9fs_session_init+0x1b9/0x28e0 fs/9p/v9fs.c:410 v9fs_mount+0xe2/0x12b0 fs/9p/vfs_super.c:122 legacy_get_tree+0x114/0x290 fs/fs_context.c:662 vfs_get_tree+0xa7/0x570 fs/super.c:1797 do_new_mount+0x71f/0x15e0 fs/namespace.c:3352 path_mount+0x742/0x1f20 fs/namespace.c:3679 do_mount fs/namespace.c:3692 [inline] __do_sys_mount fs/namespace.c:3898 [inline] __se_sys_mount+0x725/0x810 fs/namespace.c:3875 __x64_sys_mount+0xe4/0x150 fs/namespace.c:3875 do_syscall_64+0xd5/0x1f0 entry_SYSCALL_64_after_hwframe+0x6d/0x75 Uninit was created at: __alloc_pages+0x9d6/0xe70 mm/page_alloc.c:4598 __alloc_pages_node include/linux/gfp.h:238 [inline] alloc_pages_node include/linux/gfp.h:261 [inline] alloc_slab_page mm/slub.c:2175 [inline] allocate_slab mm/slub.c:2338 [inline] new_slab+0x2de/0x1400 mm/slub.c:2391 ___slab_alloc+0x1184/0x33d0 mm/slub.c:3525 __slab_alloc mm/slub.c:3610 [inline] __slab_alloc_node mm/slub.c:3663 [inline] slab_alloc_node mm/slub.c:3835 [inline] kmem_cache_alloc+0x6d3/0xbe0 mm/slub.c:3852 p9_tag_alloc net/9p/client.c:278 [inline] p9_client_prepare_req+0x20a/0x1770 net/9p/client.c:641 p9_client_rpc+0x27e/0x1340 net/9p/client.c:688 p9_client_create+0x1551/0x1ff0 net/9p/client.c:1031 v9fs_session_init+0x1b9/0x28e0 fs/9p/v9fs.c:410 v9fs_mount+0xe2/0x12b0 fs/9p/vfs_super.c:122 legacy_get_tree+0x114/0x290 fs/fs_context.c:662 vfs_get_tree+0xa7/0x570 fs/super.c:1797 do_new_mount+0x71f/0x15e0 fs/namespace.c:3352 path_mount+0x742/0x1f20 fs/namespace.c:3679 do_mount fs/namespace.c:3692 [inline] __do_sys_mount fs/namespace.c:3898 [inline] __se_sys_mount+0x725/0x810 fs/namespace.c:3875 __x64_sys_mount+0xe4/0x150 fs/namespace.c:3875 do_syscall_64+0xd5/0x1f0 entry_SYSCALL_64_after_hwframe+0x6d/0x75 If p9_check_errors() fails early in p9_client_rpc(), req->rc.tag will not be properly initialized. However, trace_9p_client_res() ends up trying to print it out anyway before p9_client_rpc() finishes. Fix this issue by assigning default values to p9_fcall fields such as 'tag' and (just in case KMSAN unearths something new) 'id' during the tag allocation stage. Reported-and-tested-by: syzbot+ff14db38f56329ef68df@syzkaller.appspotmail.com Fixes: 348b59012e5c ("net/9p: Convert net/9p protocol dumps to tracepoints") Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru> Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com> Cc: stable@vger.kernel.org Message-ID: <20240408141039.30428-1-n.zhandarovich@fintech.ru> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org> 
Syzbot with the help of KMSAN reported the following error:

BUG: KMSAN: uninit-value in trace_9p_client_res include/trace/events/9p.h:146 [inline]
BUG: KMSAN: uninit-value in p9_client_rpc+0x1314/0x1340 net/9p/client.c:754
 trace_9p_client_res include/trace/events/9p.h:146 [inline]
 p9_client_rpc+0x1314/0x1340 net/9p/client.c:754
 p9_client_create+0x1551/0x1ff0 net/9p/client.c:1031
 v9fs_session_init+0x1b9/0x28e0 fs/9p/v9fs.c:410
 v9fs_mount+0xe2/0x12b0 fs/9p/vfs_super.c:122
 legacy_get_tree+0x114/0x290 fs/fs_context.c:662
 vfs_get_tree+0xa7/0x570 fs/super.c:1797
 do_new_mount+0x71f/0x15e0 fs/namespace.c:3352
 path_mount+0x742/0x1f20 fs/namespace.c:3679
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x725/0x810 fs/namespace.c:3875
 __x64_sys_mount+0xe4/0x150 fs/namespace.c:3875
 do_syscall_64+0xd5/0x1f0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

Uninit was created at:
 __alloc_pages+0x9d6/0xe70 mm/page_alloc.c:4598
 __alloc_pages_node include/linux/gfp.h:238 [inline]
 alloc_pages_node include/linux/gfp.h:261 [inline]
 alloc_slab_page mm/slub.c:2175 [inline]
 allocate_slab mm/slub.c:2338 [inline]
 new_slab+0x2de/0x1400 mm/slub.c:2391
 ___slab_alloc+0x1184/0x33d0 mm/slub.c:3525
 __slab_alloc mm/slub.c:3610 [inline]
 __slab_alloc_node mm/slub.c:3663 [inline]
 slab_alloc_node mm/slub.c:3835 [inline]
 kmem_cache_alloc+0x6d3/0xbe0 mm/slub.c:3852
 p9_tag_alloc net/9p/client.c:278 [inline]
 p9_client_prepare_req+0x20a/0x1770 net/9p/client.c:641
 p9_client_rpc+0x27e/0x1340 net/9p/client.c:688
 p9_client_create+0x1551/0x1ff0 net/9p/client.c:1031
 v9fs_session_init+0x1b9/0x28e0 fs/9p/v9fs.c:410
 v9fs_mount+0xe2/0x12b0 fs/9p/vfs_super.c:122
 legacy_get_tree+0x114/0x290 fs/fs_context.c:662
 vfs_get_tree+0xa7/0x570 fs/super.c:1797
 do_new_mount+0x71f/0x15e0 fs/namespace.c:3352
 path_mount+0x742/0x1f20 fs/namespace.c:3679
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x725/0x810 fs/namespace.c:3875
 __x64_sys_mount+0xe4/0x150 fs/namespace.c:3875
 do_syscall_64+0xd5/0x1f0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

If p9_check_errors() fails early in p9_client_rpc(), req->rc.tag
will not be properly initialized. However, trace_9p_client_res()
ends up trying to print it out anyway before p9_client_rpc()
finishes.

Fix this issue by assigning default values to p9_fcall fields
such as 'tag' and (just in case KMSAN unearths something new) 'id'
during the tag allocation stage.

Reported-and-tested-by: syzbot+ff14db38f56329ef68df@syzkaller.appspotmail.com
Fixes: 348b59012e5c ("net/9p: Convert net/9p protocol dumps to tracepoints")
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru>
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
Cc: stable@vger.kernel.org
Message-ID: <20240408141039.30428-1-n.zhandarovich@fintech.ru>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>