From: Jinjie Ruan <ruanjinjie@huawei.com>
To: <linux-trace-kernel@vger.kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Ajay Kaher <akaher@vmware.com>
Cc: <ruanjinjie@huawei.com>
Subject: [PATCH v3] eventfs: Fix the NULL pointer dereference bug in eventfs_remove_rec()
Date: Mon, 11 Sep 2023 13:28:17 +0800 [thread overview]
Message-ID: <20230911052818.1020547-1-ruanjinjie@huawei.com> (raw)
Inject fault while probing btrfs.ko, if kstrdup() fails in
eventfs_prepare_ef() in eventfs_add_dir(), it will return ERR_PTR
to assign file->ef. But the eventfs_remove() check NULL in
trace_module_remove_events(), which causes the below NULL
pointer dereference.
As both Masami and Steven suggest, allocater side should handle the
error carefully and remove it, so fix the places where it failed.
Could not create tracefs 'raid56_write' directory
Btrfs loaded, zoned=no, fsverity=no
Unable to handle kernel NULL pointer dereference at virtual address 000000000000001c
Mem abort info:
ESR = 0x0000000096000004
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x04: level 0 translation fault
Data abort info:
ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
CM = 0, WnR = 0, TnD = 0, TagAccess = 0
GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
user pgtable: 4k pages, 48-bit VAs, pgdp=0000000102544000
[000000000000001c] pgd=0000000000000000, p4d=0000000000000000
Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
Dumping ftrace buffer:
(ftrace buffer empty)
Modules linked in: btrfs(-) libcrc32c xor xor_neon raid6_pq cfg80211 rfkill 8021q garp mrp stp llc ipv6 [last unloaded: btrfs]
CPU: 15 PID: 1343 Comm: rmmod Tainted: G N 6.5.0+ #40
Hardware name: linux,dummy-virt (DT)
pstate: 80000005 (Nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : eventfs_remove_rec+0x24/0xc0
lr : eventfs_remove+0x68/0x1d8
sp : ffff800082d63b60
x29: ffff800082d63b60 x28: ffffb84b80ddd00c x27: ffffb84b3054ba40
x26: 0000000000000002 x25: ffff800082d63bf8 x24: ffffb84b8398e440
x23: ffffb84b82af3000 x22: dead000000000100 x21: dead000000000122
x20: ffff800082d63bf8 x19: fffffffffffffff4 x18: ffffb84b82508820
x17: 0000000000000000 x16: 0000000000000000 x15: 000083bc876a3166
x14: 000000000000006d x13: 000000000000006d x12: 0000000000000000
x11: 0000000000000001 x10: 00000000000017e0 x9 : 0000000000000001
x8 : 0000000000000000 x7 : 0000000000000000 x6 : ffffb84b84289804
x5 : 0000000000000000 x4 : 9696969696969697 x3 : ffff33a5b7601f38
x2 : 0000000000000000 x1 : ffff800082d63bf8 x0 : fffffffffffffff4
Call trace:
eventfs_remove_rec+0x24/0xc0
eventfs_remove+0x68/0x1d8
remove_event_file_dir+0x88/0x100
event_remove+0x140/0x15c
trace_module_notify+0x1fc/0x230
notifier_call_chain+0x98/0x17c
blocking_notifier_call_chain+0x4c/0x74
__arm64_sys_delete_module+0x1a4/0x298
invoke_syscall+0x44/0x100
el0_svc_common.constprop.1+0x68/0xe0
do_el0_svc+0x1c/0x28
el0_svc+0x3c/0xc4
el0t_64_sync_handler+0xa0/0xc4
el0t_64_sync+0x174/0x178
Code: 5400052c a90153b3 aa0003f3 aa0103f4 (f9401400)
---[ end trace 0000000000000000 ]---
Kernel panic - not syncing: Oops: Fatal exception
SMP: stopping secondary CPUs
Dumping ftrace buffer:
(ftrace buffer empty)
Kernel Offset: 0x384b00c00000 from 0xffff800080000000
PHYS_OFFSET: 0xffffcc5b80000000
CPU features: 0x88000203,3c020000,1000421b
Memory Limit: none
Rebooting in 1 seconds..
Fixes: 5bdcd5f5331a ("eventfs: Implement removal of meta data from eventfs")
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
---
v3:
- Fix the places where it failed instead of IS_ERR_OR_NULL()
- Update the commit message.
v2:
- Use IS_ERR_OR_NULL() to check instead of IS_ERR() as suggested.
- Update the commit message.
---
fs/tracefs/event_inode.c | 22 +++++++++++-----------
kernel/trace/trace_events.c | 4 ++--
2 files changed, 13 insertions(+), 13 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 237c6f370ad9..72bf40484244 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -447,12 +447,12 @@ static struct eventfs_file *eventfs_prepare_ef(const char *name, umode_t mode,
ef = kzalloc(sizeof(*ef), GFP_KERNEL);
if (!ef)
- return ERR_PTR(-ENOMEM);
+ return NULL;
ef->name = kstrdup(name, GFP_KERNEL);
if (!ef->name) {
kfree(ef);
- return ERR_PTR(-ENOMEM);
+ return NULL;
}
if (S_ISDIR(mode)) {
@@ -460,7 +460,7 @@ static struct eventfs_file *eventfs_prepare_ef(const char *name, umode_t mode,
if (!ef->ei) {
kfree(ef->name);
kfree(ef);
- return ERR_PTR(-ENOMEM);
+ return NULL;
}
INIT_LIST_HEAD(&ef->ei->e_top_files);
} else {
@@ -539,14 +539,14 @@ struct eventfs_file *eventfs_add_subsystem_dir(const char *name,
struct eventfs_file *ef;
if (!parent)
- return ERR_PTR(-EINVAL);
+ return NULL;
ti_parent = get_tracefs(parent->d_inode);
ei_parent = ti_parent->private;
ef = eventfs_prepare_ef(name, S_IFDIR, NULL, NULL, NULL);
- if (IS_ERR(ef))
- return ef;
+ if (!ef)
+ return NULL;
mutex_lock(&eventfs_mutex);
list_add_tail(&ef->list, &ei_parent->e_top_files);
@@ -570,11 +570,11 @@ struct eventfs_file *eventfs_add_dir(const char *name,
struct eventfs_file *ef;
if (!ef_parent)
- return ERR_PTR(-EINVAL);
+ return NULL;
ef = eventfs_prepare_ef(name, S_IFDIR, NULL, NULL, NULL);
- if (IS_ERR(ef))
- return ef;
+ if (!ef)
+ return NULL;
mutex_lock(&eventfs_mutex);
list_add_tail(&ef->list, &ef_parent->ei->e_top_files);
@@ -622,7 +622,7 @@ int eventfs_add_events_file(const char *name, umode_t mode,
ei = ti->private;
ef = eventfs_prepare_ef(name, mode, fop, NULL, data);
- if (IS_ERR(ef))
+ if (!ef)
return -ENOMEM;
mutex_lock(&eventfs_mutex);
@@ -661,7 +661,7 @@ int eventfs_add_file(const char *name, umode_t mode,
mode |= S_IFREG;
ef = eventfs_prepare_ef(name, mode, fop, NULL, data);
- if (IS_ERR(ef))
+ if (!ef)
return -ENOMEM;
mutex_lock(&eventfs_mutex);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index ed367d713be0..86956e23ac49 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2330,7 +2330,7 @@ event_subsystem_dir(struct trace_array *tr, const char *name,
__get_system(system);
dir->ef = eventfs_add_subsystem_dir(name, parent);
- if (IS_ERR(dir->ef)) {
+ if (!dir->ef) {
pr_warn("Failed to create system directory %s\n", name);
__put_system(system);
goto out_free;
@@ -2432,7 +2432,7 @@ event_create_dir(struct dentry *parent, struct trace_event_file *file)
name = trace_event_name(call);
file->ef = eventfs_add_dir(name, ef_subsystem);
- if (IS_ERR(file->ef)) {
+ if (!file->ef) {
pr_warn("Could not create tracefs '%s' directory\n", name);
return -1;
}
--
2.34.1
next reply other threads:[~2023-09-11 5:28 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-11 5:28 Jinjie Ruan [this message]
2023-09-11 11:51 ` [PATCH v3] eventfs: Fix the NULL pointer dereference bug in eventfs_remove_rec() Masami Hiramatsu
2023-09-11 21:39 ` Steven Rostedt
2023-09-12 2:36 ` Ruan Jinjie
2023-09-12 2:35 ` Ruan Jinjie
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