When debugfs file is opened, its module should not be removed until
it's closed.
Because debugfs internally uses the module's data.
So, it could access freed memory.
In order to avoid panic, it just sets .owner to THIS_MODULE.
So that all modules will be held when its debugfs file is opened.
Test commands:
cat <<EOF > open.c
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
int main(int argc, char *argv[])
{
int fd = open(argv[1], O_RDONLY);
if(fd < 0) {
printf("failed to open\n");
return 1;
}
usleep(3000000);
close(fd);
return 0;
}
EOF
gcc -o open open.c
modprobe netdevsim
echo 1 > /sys/bus/netdevsim/new_device
./open /sys/kernel/debug/netdevsim/netdevsim1/take_snapshot &
modprobe -rv netdevsim
Splat looks like:
[ 75.305876][ T662] BUG: unable to handle page fault for address: fffffbfff8096db4
[ 75.308979][ T662] #PF: supervisor read access in kernel mode
[ 75.311311][ T662] #PF: error_code(0x0000) - not-present page
[ 75.313737][ T662] PGD 1237ee067 P4D 1237ee067 PUD 123612067 PMD 100ba7067 PTE 0
[ 75.316858][ T662] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI
[ 75.319389][ T662] CPU: 1 PID: 662 Comm: open Not tainted 5.10.0-rc2+ #785
[ 75.322312][ T662] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
[ 75.326429][ T662] RIP: 0010:full_proxy_release+0xca/0x290
[ 75.328712][ T662] Code: c1 ea 03 80 3c 02 00 0f 85 60 01 00 00 49 8d bc 24 80 00 00 00 4c 8b 73 28 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 71 01 00 00 49 8b 84 24 80 00 00 00 48 85 c0 0f
[ 75.336716][ T662] RSP: 0018:ffff88800400fe48 EFLAGS: 00010a06
[ 75.339153][ T662] RAX: dffffc0000000000 RBX: ffff88810139de00 RCX: ffff88810139de28
[ 75.342419][ T662] RDX: 1ffffffff8096db4 RSI: ffff88810139de00 RDI: ffffffffc04b6da0
[ 75.345629][ T662] RBP: ffff8881168342b0 R08: ffff8881168342b0 R09: ffff888110765300
[ 75.348804][ T662] R10: ffff88800400fe88 R11: ffffed1022ac648a R12: ffffffffc04b6d20
[ 75.352052][ T662] R13: ffff88810139de28 R14: ffff8881054a6d00 R15: ffff888110765300
[ 75.355325][ T662] FS: 00007f937b80f4c0(0000) GS:ffff888118e00000(0000) knlGS:0000000000000000
[ 75.358955][ T662] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 75.361634][ T662] CR2: fffffbfff8096db4 CR3: 0000000004292002 CR4: 00000000003706e0
[ 75.364847][ T662] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 75.368003][ T662] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 75.371259][ T662] Call Trace:
[ 75.372655][ T662] __fput+0x1ff/0x820
[ 75.374316][ T662] ? _raw_spin_unlock_irq+0x24/0x30
[ 75.376454][ T662] task_work_run+0xd3/0x170
[ 75.378268][ T662] exit_to_user_mode_prepare+0x14b/0x150
[ 75.380586][ T662] syscall_exit_to_user_mode+0x40/0x250
[ 75.383015][ T662] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 75.385427][ T662] RIP: 0033:0x7f937b3159e4
[ ... ]
v1 -> v2:
- Rebase
- Squash patches into per-driver/subsystem
Taehee Yoo (21):
net: set .owner to THIS_MODULE
mac80211: set .owner to THIS_MODULE
cfg80211: set .owner to THIS_MODULE
netdevsim: set .owner to THIS_MODULE
ieee802154: set .owner to THIS_MODULE
i2400m: set .owner to THIS_MODULE
wlcore: set .owner to THIS_MODULE
wl1251: set .owner to THIS_MODULE
iwlwifi: set .owner to THIS_MODULE
iwlegacy: set .owner to THIS_MODULE
rtlwifi: set .owner to THIS_MODULE
ath11k: set .owner to THIS_MODULE
ath10k: set .owner to THIS_MODULE
wcn36xx: set .owner to THIS_MODULE
wil6210: set .owner to THIS_MODULE
cw1200: set .owner to THIS_MODULE
brcmfmac: set .owner to THIS_MODULE
b43legacy: set .owner to THIS_MODULE
b43: set .owner to THIS_MODULE
mwifiex: mwifiex: set .owner to THIS_MODULE
Bluetooth: set .owner to THIS_MODULE
drivers/net/ieee802154/ca8210.c | 3 ++-
drivers/net/netdevsim/dev.c | 2 ++
drivers/net/netdevsim/health.c | 1 +
drivers/net/netdevsim/udp_tunnels.c | 1 +
drivers/net/wimax/i2400m/debugfs.c | 2 ++
drivers/net/wireless/ath/ath10k/debug.c | 15 ++++++++++-----
drivers/net/wireless/ath/ath11k/debugfs.c | 7 +++++--
drivers/net/wireless/ath/wcn36xx/debug.c | 2 ++
drivers/net/wireless/ath/wil6210/debugfs.c | 19 +++++++++++++++++++
drivers/net/wireless/broadcom/b43/debugfs.c | 1 +
.../net/wireless/broadcom/b43legacy/debugfs.c | 1 +
.../broadcom/brcm80211/brcmfmac/core.c | 1 +
drivers/net/wireless/intel/iwlegacy/3945-rs.c | 1 +
drivers/net/wireless/intel/iwlegacy/4965-rs.c | 3 +++
drivers/net/wireless/intel/iwlegacy/debug.c | 3 +++
.../net/wireless/intel/iwlwifi/dvm/debugfs.c | 3 +++
drivers/net/wireless/intel/iwlwifi/dvm/rs.c | 3 +++
.../net/wireless/intel/iwlwifi/fw/debugfs.c | 3 +++
.../net/wireless/intel/iwlwifi/mvm/debugfs.c | 1 +
.../net/wireless/intel/iwlwifi/mvm/debugfs.h | 3 +++
drivers/net/wireless/intel/iwlwifi/mvm/rs.c | 3 +++
.../net/wireless/intel/iwlwifi/pcie/trans.c | 3 +++
.../net/wireless/marvell/mwifiex/debugfs.c | 3 +++
drivers/net/wireless/realtek/rtlwifi/debug.c | 1 +
drivers/net/wireless/st/cw1200/debug.c | 1 +
drivers/net/wireless/ti/wl1251/debugfs.c | 4 ++++
drivers/net/wireless/ti/wlcore/debugfs.h | 3 +++
net/6lowpan/debugfs.c | 1 +
net/batman-adv/log.c | 1 +
net/bluetooth/6lowpan.c | 1 +
net/bluetooth/hci_core.c | 2 ++
net/bluetooth/hci_debugfs.c | 6 ++++++
net/bluetooth/selftest.c | 1 +
net/bluetooth/smp.c | 2 ++
net/mac80211/debugfs.c | 7 +++++++
net/mac80211/debugfs_key.c | 3 +++
net/mac80211/debugfs_netdev.c | 1 +
net/mac80211/debugfs_sta.c | 2 ++
net/mac80211/rate.c | 1 +
net/mac80211/rc80211_minstrel_ht_debugfs.c | 2 ++
net/wireless/debugfs.c | 2 ++
41 files changed, 117 insertions(+), 8 deletions(-)
--
2.17.1
