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Andrew Gabbasov 8aa1cb46b7 usb: gadget: f_fs: Fix setting of device and driver data cross-references
[ Upstream commit ecfbd7b9054bddb12cea07fda41bb3a79a7b0149 ]

FunctionFS device structure 'struct ffs_dev' and driver data structure
'struct ffs_data' are bound to each other with cross-reference pointers
'ffs_data->private_data' and 'ffs_dev->ffs_data'. While the first one
is supposed to be valid through the whole life of 'struct ffs_data'
(and while 'struct ffs_dev' exists non-freed), the second one is cleared
in 'ffs_closed()' (called from 'ffs_data_reset()' or the last
'ffs_data_put()'). This can be called several times, alternating in
different order with 'ffs_free_inst()', that, if possible, clears
the other cross-reference.

As a result, different cases of these calls order may leave stale
cross-reference pointers, used when the pointed structure is already
freed. Even if it occasionally doesn't cause kernel crash, this error
is reported by KASAN-enabled kernel configuration.

For example, the case [last 'ffs_data_put()' - 'ffs_free_inst()'] was
fixed by commit cdafb6d8b8 ("usb: gadget: f_fs: Fix use-after-free in
ffs_free_inst").

The other case ['ffs_data_reset()' - 'ffs_free_inst()' - 'ffs_data_put()']
now causes KASAN reported error [1], when 'ffs_data_reset()' clears
'ffs_dev->ffs_data', then 'ffs_free_inst()' frees the 'struct ffs_dev',
but can't clear 'ffs_data->private_data', which is then accessed
in 'ffs_closed()' called from 'ffs_data_put()'. This happens since
'ffs_dev->ffs_data' reference is cleared too early.

Moreover, one more use case, when 'ffs_free_inst()' is called immediately
after mounting FunctionFS device (that is before the descriptors are
written and 'ffs_ready()' is called), and then 'ffs_data_reset()'
or 'ffs_data_put()' is called from accessing "ep0" file or unmounting
the device. This causes KASAN error report like [2], since
'ffs_dev->ffs_data' is not yet set when 'ffs_free_inst()' can't properly
clear 'ffs_data->private_data', that is later accessed to freed structure.

Fix these (and may be other) cases of stale pointers access by moving
setting and clearing of the mentioned cross-references to the single
places, setting both of them when 'struct ffs_data' is created and
bound to 'struct ffs_dev', and clearing both of them when one of the
structures is destroyed. It seems convenient to make this pointer
initialization and structures binding in 'ffs_acquire_dev()' and
make pointers clearing in 'ffs_release_dev()'. This required some
changes in these functions parameters and return types.

Also, 'ffs_release_dev()' calling requires some cleanup, fixing minor
issues, like (1) 'ffs_release_dev()' is not called if 'ffs_free_inst()'
is called without unmounting the device, and "release_dev" callback
is not called at all, or (2) "release_dev" callback is called before
"ffs_closed" callback on unmounting, which seems to be not correctly
nested with "acquire_dev" and "ffs_ready" callbacks.
Make this cleanup togther with other mentioned 'ffs_release_dev()' changes.

[1]
==================================================================
root@rcar-gen3:~# mkdir /dev/cfs
root@rcar-gen3:~# mkdir /dev/ffs
root@rcar-gen3:~# modprobe libcomposite
root@rcar-gen3:~# mount -t configfs none /dev/cfs
root@rcar-gen3:~# mkdir /dev/cfs/usb_gadget/g1
root@rcar-gen3:~# mkdir /dev/cfs/usb_gadget/g1/functions/ffs.ffs
[   64.340664] file system registered
root@rcar-gen3:~# mount -t functionfs ffs /dev/ffs
root@rcar-gen3:~# cd /dev/ffs
root@rcar-gen3:/dev/ffs# /home/root/ffs-test
ffs-test: info: ep0: writing descriptors (in v2 format)
[   83.181442] read descriptors
[   83.186085] read strings
ffs-test: info: ep0: writing strings
ffs-test: dbg:  ep1: starting
ffs-test: dbg:  ep2: starting
ffs-test: info: ep1: starts
ffs-test: info: ep2: starts
ffs-test: info: ep0: starts

^C
root@rcar-gen3:/dev/ffs# cd /home/root/
root@rcar-gen3:~# rmdir /dev/cfs/usb_gadget/g1/functions/ffs.ffs
[   98.935061] unloading
root@rcar-gen3:~# umount /dev/ffs
[  102.734301] ==================================================================
[  102.742059] BUG: KASAN: use-after-free in ffs_release_dev+0x64/0xa8 [usb_f_fs]
[  102.749683] Write of size 1 at addr ffff0004d46ff549 by task umount/2997
[  102.756709]
[  102.758311] CPU: 0 PID: 2997 Comm: umount Not tainted 5.13.0-rc4+ #8
[  102.764971] Hardware name: Renesas Salvator-X board based on r8a77951 (DT)
[  102.772179] Call trace:
[  102.774779]  dump_backtrace+0x0/0x330
[  102.778653]  show_stack+0x20/0x2c
[  102.782152]  dump_stack+0x11c/0x1ac
[  102.785833]  print_address_description.constprop.0+0x30/0x274
[  102.791862]  kasan_report+0x14c/0x1c8
[  102.795719]  __asan_report_store1_noabort+0x34/0x58
[  102.800840]  ffs_release_dev+0x64/0xa8 [usb_f_fs]
[  102.805801]  ffs_fs_kill_sb+0x50/0x84 [usb_f_fs]
[  102.810663]  deactivate_locked_super+0xa0/0xf0
[  102.815339]  deactivate_super+0x98/0xac
[  102.819378]  cleanup_mnt+0xd0/0x1b0
[  102.823057]  __cleanup_mnt+0x1c/0x28
[  102.826823]  task_work_run+0x104/0x180
[  102.830774]  do_notify_resume+0x458/0x14e0
[  102.835083]  work_pending+0xc/0x5f8
[  102.838762]
[  102.840357] Allocated by task 2988:
[  102.844032]  kasan_save_stack+0x28/0x58
[  102.848071]  kasan_set_track+0x28/0x3c
[  102.852016]  ____kasan_kmalloc+0x84/0x9c
[  102.856142]  __kasan_kmalloc+0x10/0x1c
[  102.860088]  __kmalloc+0x214/0x2f8
[  102.863678]  kzalloc.constprop.0+0x14/0x20 [usb_f_fs]
[  102.868990]  ffs_alloc_inst+0x8c/0x208 [usb_f_fs]
[  102.873942]  try_get_usb_function_instance+0xf0/0x164 [libcomposite]
[  102.880629]  usb_get_function_instance+0x64/0x68 [libcomposite]
[  102.886858]  function_make+0x128/0x1ec [libcomposite]
[  102.892185]  configfs_mkdir+0x330/0x590 [configfs]
[  102.897245]  vfs_mkdir+0x12c/0x1bc
[  102.900835]  do_mkdirat+0x180/0x1d0
[  102.904513]  __arm64_sys_mkdirat+0x80/0x94
[  102.908822]  invoke_syscall+0xf8/0x25c
[  102.912772]  el0_svc_common.constprop.0+0x150/0x1a0
[  102.917891]  do_el0_svc+0xa0/0xd4
[  102.921386]  el0_svc+0x24/0x34
[  102.924613]  el0_sync_handler+0xcc/0x154
[  102.928743]  el0_sync+0x198/0x1c0
[  102.932238]
[  102.933832] Freed by task 2996:
[  102.937144]  kasan_save_stack+0x28/0x58
[  102.941181]  kasan_set_track+0x28/0x3c
[  102.945128]  kasan_set_free_info+0x28/0x4c
[  102.949435]  ____kasan_slab_free+0x104/0x118
[  102.953921]  __kasan_slab_free+0x18/0x24
[  102.958047]  slab_free_freelist_hook+0x148/0x1f0
[  102.962897]  kfree+0x318/0x440
[  102.966123]  ffs_free_inst+0x164/0x2d8 [usb_f_fs]
[  102.971075]  usb_put_function_instance+0x84/0xa4 [libcomposite]
[  102.977302]  ffs_attr_release+0x18/0x24 [usb_f_fs]
[  102.982344]  config_item_put+0x140/0x1a4 [configfs]
[  102.987486]  configfs_rmdir+0x3fc/0x518 [configfs]
[  102.992535]  vfs_rmdir+0x114/0x234
[  102.996122]  do_rmdir+0x274/0x2b0
[  102.999617]  __arm64_sys_unlinkat+0x94/0xc8
[  103.004015]  invoke_syscall+0xf8/0x25c
[  103.007961]  el0_svc_common.constprop.0+0x150/0x1a0
[  103.013080]  do_el0_svc+0xa0/0xd4
[  103.016575]  el0_svc+0x24/0x34
[  103.019801]  el0_sync_handler+0xcc/0x154
[  103.023930]  el0_sync+0x198/0x1c0
[  103.027426]
[  103.029020] The buggy address belongs to the object at ffff0004d46ff500
[  103.029020]  which belongs to the cache kmalloc-128 of size 128
[  103.042079] The buggy address is located 73 bytes inside of
[  103.042079]  128-byte region [ffff0004d46ff500, ffff0004d46ff580)
[  103.054236] The buggy address belongs to the page:
[  103.059262] page:0000000021aa849b refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff0004d46fee00 pfn:0x5146fe
[  103.070437] head:0000000021aa849b order:1 compound_mapcount:0
[  103.076456] flags: 0x8000000000010200(slab|head|zone=2)
[  103.081948] raw: 8000000000010200 fffffc0013521a80 0000000d0000000d ffff0004c0002300
[  103.090052] raw: ffff0004d46fee00 000000008020001e 00000001ffffffff 0000000000000000
[  103.098150] page dumped because: kasan: bad access detected
[  103.103985]
[  103.105578] Memory state around the buggy address:
[  103.110602]  ffff0004d46ff400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  103.118161]  ffff0004d46ff480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  103.125726] >ffff0004d46ff500: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  103.133284]                                               ^
[  103.139120]  ffff0004d46ff580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  103.146679]  ffff0004d46ff600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  103.154238] ==================================================================
[  103.161792] Disabling lock debugging due to kernel taint
[  103.167319] Unable to handle kernel paging request at virtual address 0037801d6000018e
[  103.175406] Mem abort info:
[  103.178457]   ESR = 0x96000004
[  103.181609]   EC = 0x25: DABT (current EL), IL = 32 bits
[  103.187020]   SET = 0, FnV = 0
[  103.190185]   EA = 0, S1PTW = 0
[  103.193417] Data abort info:
[  103.196385]   ISV = 0, ISS = 0x00000004
[  103.200315]   CM = 0, WnR = 0
[  103.203366] [0037801d6000018e] address between user and kernel address ranges
[  103.210611] Internal error: Oops: 96000004 [#1] PREEMPT SMP
[  103.216231] Modules linked in: usb_f_fs libcomposite configfs ath9k_htc led_class mac80211 libarc4 ath9k_common ath9k_hw ath cfg80211 aes_ce_blk sata_rc4
[  103.259233] CPU: 0 PID: 2997 Comm: umount Tainted: G    B             5.13.0-rc4+ #8
[  103.267031] Hardware name: Renesas Salvator-X board based on r8a77951 (DT)
[  103.273951] pstate: 00000005 (nzcv daif -PAN -UAO -TCO BTYPE=--)
[  103.280001] pc : ffs_data_clear+0x138/0x370 [usb_f_fs]
[  103.285197] lr : ffs_data_clear+0x124/0x370 [usb_f_fs]
[  103.290385] sp : ffff800014777a80
[  103.293725] x29: ffff800014777a80 x28: ffff0004d7649c80 x27: 0000000000000000
[  103.300931] x26: ffff800014777fb0 x25: ffff60009aec9394 x24: ffff0004d7649ca4
[  103.308136] x23: 1fffe0009a3d063a x22: dfff800000000000 x21: ffff0004d1e831d0
[  103.315340] x20: e1c000eb00000bb4 x19: ffff0004d1e83000 x18: 0000000000000000
[  103.322545] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
[  103.329748] x14: 0720072007200720 x13: 0720072007200720 x12: 1ffff000012ef658
[  103.336952] x11: ffff7000012ef658 x10: 0720072007200720 x9 : ffff800011322648
[  103.344157] x8 : ffff800014777818 x7 : ffff80000977b2c7 x6 : 0000000000000000
[  103.351359] x5 : 0000000000000001 x4 : ffff7000012ef659 x3 : 0000000000000001
[  103.358562] x2 : 0000000000000000 x1 : 1c38001d6000018e x0 : e1c000eb00000c70
[  103.365766] Call trace:
[  103.368235]  ffs_data_clear+0x138/0x370 [usb_f_fs]
[  103.373076]  ffs_data_reset+0x20/0x304 [usb_f_fs]
[  103.377829]  ffs_data_closed+0x1ec/0x244 [usb_f_fs]
[  103.382755]  ffs_fs_kill_sb+0x70/0x84 [usb_f_fs]
[  103.387420]  deactivate_locked_super+0xa0/0xf0
[  103.391905]  deactivate_super+0x98/0xac
[  103.395776]  cleanup_mnt+0xd0/0x1b0
[  103.399299]  __cleanup_mnt+0x1c/0x28
[  103.402906]  task_work_run+0x104/0x180
[  103.406691]  do_notify_resume+0x458/0x14e0
[  103.410823]  work_pending+0xc/0x5f8
[  103.414351] Code: b4000a54 9102f280 12000802 d343fc01 (38f66821)
[  103.420490] ---[ end trace 57b43a50e8244f57 ]---
Segmentation fault
root@rcar-gen3:~#
==================================================================

[2]
==================================================================
root@rcar-gen3:~# mkdir /dev/ffs
root@rcar-gen3:~# modprobe libcomposite
root@rcar-gen3:~#
root@rcar-gen3:~# mount -t configfs none /dev/cfs
root@rcar-gen3:~# mkdir /dev/cfs/usb_gadget/g1
root@rcar-gen3:~# mkdir /dev/cfs/usb_gadget/g1/functions/ffs.ffs
[   54.766480] file system registered
root@rcar-gen3:~# mount -t functionfs ffs /dev/ffs
root@rcar-gen3:~# rmdir /dev/cfs/usb_gadget/g1/functions/ffs.ffs
[   63.197597] unloading
root@rcar-gen3:~# cat /dev/ffs/ep0
cat: read error:[   67.213506] ==================================================================
[   67.222095] BUG: KASAN: use-after-free in ffs_data_clear+0x70/0x370 [usb_f_fs]
[   67.229699] Write of size 1 at addr ffff0004c26e974a by task cat/2994
[   67.236446]
[   67.238045] CPU: 0 PID: 2994 Comm: cat Not tainted 5.13.0-rc4+ #8
[   67.244431] Hardware name: Renesas Salvator-X board based on r8a77951 (DT)
[   67.251624] Call trace:
[   67.254212]  dump_backtrace+0x0/0x330
[   67.258081]  show_stack+0x20/0x2c
[   67.261579]  dump_stack+0x11c/0x1ac
[   67.265260]  print_address_description.constprop.0+0x30/0x274
[   67.271286]  kasan_report+0x14c/0x1c8
[   67.275143]  __asan_report_store1_noabort+0x34/0x58
[   67.280265]  ffs_data_clear+0x70/0x370 [usb_f_fs]
[   67.285220]  ffs_data_reset+0x20/0x304 [usb_f_fs]
[   67.290172]  ffs_data_closed+0x240/0x244 [usb_f_fs]
[   67.295305]  ffs_ep0_release+0x40/0x54 [usb_f_fs]
[   67.300256]  __fput+0x304/0x580
[   67.303576]  ____fput+0x18/0x24
[   67.306893]  task_work_run+0x104/0x180
[   67.310846]  do_notify_resume+0x458/0x14e0
[   67.315154]  work_pending+0xc/0x5f8
[   67.318834]
[   67.320429] Allocated by task 2988:
[   67.324105]  kasan_save_stack+0x28/0x58
[   67.328144]  kasan_set_track+0x28/0x3c
[   67.332090]  ____kasan_kmalloc+0x84/0x9c
[   67.336217]  __kasan_kmalloc+0x10/0x1c
[   67.340163]  __kmalloc+0x214/0x2f8
[   67.343754]  kzalloc.constprop.0+0x14/0x20 [usb_f_fs]
[   67.349066]  ffs_alloc_inst+0x8c/0x208 [usb_f_fs]
[   67.354017]  try_get_usb_function_instance+0xf0/0x164 [libcomposite]
[   67.360705]  usb_get_function_instance+0x64/0x68 [libcomposite]
[   67.366934]  function_make+0x128/0x1ec [libcomposite]
[   67.372260]  configfs_mkdir+0x330/0x590 [configfs]
[   67.377320]  vfs_mkdir+0x12c/0x1bc
[   67.380911]  do_mkdirat+0x180/0x1d0
[   67.384589]  __arm64_sys_mkdirat+0x80/0x94
[   67.388899]  invoke_syscall+0xf8/0x25c
[   67.392850]  el0_svc_common.constprop.0+0x150/0x1a0
[   67.397969]  do_el0_svc+0xa0/0xd4
[   67.401464]  el0_svc+0x24/0x34
[   67.404691]  el0_sync_handler+0xcc/0x154
[   67.408819]  el0_sync+0x198/0x1c0
[   67.412315]
[   67.413909] Freed by task 2993:
[   67.417220]  kasan_save_stack+0x28/0x58
[   67.421257]  kasan_set_track+0x28/0x3c
[   67.425204]  kasan_set_free_info+0x28/0x4c
[   67.429513]  ____kasan_slab_free+0x104/0x118
[   67.434001]  __kasan_slab_free+0x18/0x24
[   67.438128]  slab_free_freelist_hook+0x148/0x1f0
[   67.442978]  kfree+0x318/0x440
[   67.446205]  ffs_free_inst+0x164/0x2d8 [usb_f_fs]
[   67.451156]  usb_put_function_instance+0x84/0xa4 [libcomposite]
[   67.457385]  ffs_attr_release+0x18/0x24 [usb_f_fs]
[   67.462428]  config_item_put+0x140/0x1a4 [configfs]
[   67.467570]  configfs_rmdir+0x3fc/0x518 [configfs]
[   67.472626]  vfs_rmdir+0x114/0x234
[   67.476215]  do_rmdir+0x274/0x2b0
[   67.479710]  __arm64_sys_unlinkat+0x94/0xc8
[   67.484108]  invoke_syscall+0xf8/0x25c
[   67.488055]  el0_svc_common.constprop.0+0x150/0x1a0
[   67.493175]  do_el0_svc+0xa0/0xd4
[   67.496671]  el0_svc+0x24/0x34
[   67.499896]  el0_sync_handler+0xcc/0x154
[   67.504024]  el0_sync+0x198/0x1c0
[   67.507520]
[   67.509114] The buggy address belongs to the object at ffff0004c26e9700
[   67.509114]  which belongs to the cache kmalloc-128 of size 128
[   67.522171] The buggy address is located 74 bytes inside of
[   67.522171]  128-byte region [ffff0004c26e9700, ffff0004c26e9780)
[   67.534328] The buggy address belongs to the page:
[   67.539355] page:000000003177a217 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5026e8
[   67.549175] head:000000003177a217 order:1 compound_mapcount:0
[   67.555195] flags: 0x8000000000010200(slab|head|zone=2)
[   67.560687] raw: 8000000000010200 fffffc0013037100 0000000c00000002 ffff0004c0002300
[   67.568791] raw: 0000000000000000 0000000080200020 00000001ffffffff 0000000000000000
[   67.576890] page dumped because: kasan: bad access detected
[   67.582725]
[   67.584318] Memory state around the buggy address:
[   67.589343]  ffff0004c26e9600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   67.596903]  ffff0004c26e9680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[   67.604463] >ffff0004c26e9700: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   67.612022]                                               ^
[   67.617860]  ffff0004c26e9780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[   67.625421]  ffff0004c26e9800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   67.632981] ==================================================================
[   67.640535] Disabling lock debugging due to kernel taint
 File descriptor[   67.646100] Unable to handle kernel paging request at virtual address fabb801d4000018d
 in bad state
[   67.655456] Mem abort info:
[   67.659619]   ESR = 0x96000004
[   67.662801]   EC = 0x25: DABT (current EL), IL = 32 bits
[   67.668225]   SET = 0, FnV = 0
[   67.671375]   EA = 0, S1PTW = 0
[   67.674613] Data abort info:
[   67.677587]   ISV = 0, ISS = 0x00000004
[   67.681522]   CM = 0, WnR = 0
[   67.684588] [fabb801d4000018d] address between user and kernel address ranges
[   67.691849] Internal error: Oops: 96000004 [#1] PREEMPT SMP
[   67.697470] Modules linked in: usb_f_fs libcomposite configfs ath9k_htc led_class mac80211 libarc4 ath9k_common ath9k_hw ath cfg80211 aes_ce_blk crypto_simd cryptd aes_ce_cipher ghash_ce gf128mul sha2_ce sha1_ce evdev sata_rcar libata xhci_plat_hcd scsi_mod xhci_hcd rene4
[   67.740467] CPU: 0 PID: 2994 Comm: cat Tainted: G    B             5.13.0-rc4+ #8
[   67.748005] Hardware name: Renesas Salvator-X board based on r8a77951 (DT)
[   67.754924] pstate: 00000005 (nzcv daif -PAN -UAO -TCO BTYPE=--)
[   67.760974] pc : ffs_data_clear+0x138/0x370 [usb_f_fs]
[   67.766178] lr : ffs_data_clear+0x124/0x370 [usb_f_fs]
[   67.771365] sp : ffff800014767ad0
[   67.774706] x29: ffff800014767ad0 x28: ffff800009cf91c0 x27: ffff0004c54861a0
[   67.781913] x26: ffff0004dc90b288 x25: 1fffe00099ec10f5 x24: 00000000000a801d
[   67.789118] x23: 1fffe00099f6953a x22: dfff800000000000 x21: ffff0004cfb4a9d0
[   67.796322] x20: d5e000ea00000bb1 x19: ffff0004cfb4a800 x18: 0000000000000000
[   67.803526] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
[   67.810730] x14: 0720072007200720 x13: 0720072007200720 x12: 1ffff000028ecefa
[   67.817934] x11: ffff7000028ecefa x10: 0720072007200720 x9 : ffff80001132c014
[   67.825137] x8 : ffff8000147677d8 x7 : ffff8000147677d7 x6 : 0000000000000000
[   67.832341] x5 : 0000000000000001 x4 : ffff7000028ecefb x3 : 0000000000000001
[   67.839544] x2 : 0000000000000005 x1 : 1abc001d4000018d x0 : d5e000ea00000c6d
[   67.846748] Call trace:
[   67.849218]  ffs_data_clear+0x138/0x370 [usb_f_fs]
[   67.854058]  ffs_data_reset+0x20/0x304 [usb_f_fs]
[   67.858810]  ffs_data_closed+0x240/0x244 [usb_f_fs]
[   67.863736]  ffs_ep0_release+0x40/0x54 [usb_f_fs]
[   67.868488]  __fput+0x304/0x580
[   67.871665]  ____fput+0x18/0x24
[   67.874837]  task_work_run+0x104/0x180
[   67.878622]  do_notify_resume+0x458/0x14e0
[   67.882754]  work_pending+0xc/0x5f8
[   67.886282] Code: b4000a54 9102f280 12000802 d343fc01 (38f66821)
[   67.892422] ---[ end trace 6d7cedf53d7abbea ]---
Segmentation fault
root@rcar-gen3:~#
==================================================================

Fixes: 4b187fceec ("usb: gadget: FunctionFS: add devices management code")
Fixes: 3262ad8243 ("usb: gadget: f_fs: Stop ffs_closed NULL pointer dereference")
Fixes: cdafb6d8b8 ("usb: gadget: f_fs: Fix use-after-free in ffs_free_inst")
Reported-by: Bhuvanesh Surachari <bhuvanesh_surachari@mentor.com>
Tested-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Reviewed-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: Andrew Gabbasov <andrew_gabbasov@mentor.com>
Link: https://lore.kernel.org/r/20210603171507.22514-1-andrew_gabbasov@mentor.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14 16:56:43 +02:00
arch s390: appldata depends on PROC_SYSCTL 2021-07-14 16:56:42 +02:00
block blk-mq: update hctx->dispatch_busy in case of real scheduler 2021-07-14 16:56:13 +02:00
certs certs: Add ability to preload revocation certs 2021-06-30 08:47:30 -04:00
crypto crypto: sm2 - fix a memory leak in sm2 2021-07-14 16:56:06 +02:00
Documentation mm/debug_vm_pgtable/basic: add validation for dirtiness after write protect 2021-07-14 16:56:13 +02:00
drivers usb: gadget: f_fs: Fix setting of device and driver data cross-references 2021-07-14 16:56:43 +02:00
fs writeback: fix obtain a reference to a freeing memcg css 2021-07-14 16:56:31 +02:00
include iio: cros_ec_sensors: Fix alignment of buffer in iio_push_to_buffers_with_timestamp() 2021-07-14 16:56:37 +02:00
init sched/core: Initialize the idle task with preemption disabled 2021-07-14 16:55:50 +02:00
ipc ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry 2021-05-26 12:06:54 +02:00
kernel rcu: Invoke rcu_spawn_core_kthreads() from rcu_spawn_gp_kthread() 2021-07-14 16:56:33 +02:00
lib lockdep/selftests: Fix selftests vs PROVE_RAW_LOCK_NESTING 2021-07-14 16:56:10 +02:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm mm/page_alloc: fix counting of managed_pages 2021-07-14 16:56:14 +02:00
net net: tipc: fix FB_MTU eat two pages 2021-07-14 16:56:32 +02:00
samples samples/bpf: Fix the error return code of xdp_redirect's main() 2021-07-14 16:56:23 +02:00
scripts kbuild: Fix objtool dependency for 'OBJECT_FILES_NON_STANDARD_<obj> := n' 2021-07-14 16:56:04 +02:00
security evm: fix writing <securityfs>/evm overflow 2021-07-14 16:56:04 +02:00
sound ASoC: mediatek: mtk-btcvsd: Fix an error handling path in 'mtk_btcvsd_snd_probe()' 2021-07-14 16:56:43 +02:00
tools selftests: splice: Adjust for handler fallback removal 2021-07-14 16:56:42 +02:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt KVM: do not allow mapping valid but non-reference-counted pages 2021-06-30 08:47:25 -04:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore kbuild: generate Module.symvers only when vmlinux exists 2021-05-19 10:12:59 +02:00
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS f2fs: move ioctl interface definitions to separated file 2021-05-19 10:13:00 +02:00
Makefile Makefile: fix GDB warning with CONFIG_RELR 2021-07-14 16:55:53 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.