* [PATCH v2] eventfs: Fix the NULL pointer dereference bug in eventfs_remove_rec()
@ 2023-09-09 7:28 Jinjie Ruan
2023-09-09 9:48 ` Masami Hiramatsu
0 siblings, 1 reply; 4+ messages in thread
From: Jinjie Ruan @ 2023-09-09 7:28 UTC (permalink / raw)
To: linux-trace-kernel, Steven Rostedt, Masami Hiramatsu, Ajay Kaher
Cc: ruanjinjie
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, use IS_ERR_OR_NULL() to
check ef in eventfs_remove_rec(), and fix the same issue
in eventfs_remove().
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>
---
v2:
- Use IS_ERR_OR_NULL() to check instead of IS_ERR() as suggested.
- Update the commit message.
---
fs/tracefs/event_inode.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 237c6f370ad9..c354b6013881 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -693,7 +693,7 @@ static void eventfs_remove_rec(struct eventfs_file *ef, struct list_head *head,
{
struct eventfs_file *ef_child;
- if (!ef)
+ if (IS_ERR_OR_NULL(ef))
return;
/*
* Check recursion depth. It should never be greater than 3:
@@ -730,7 +730,7 @@ void eventfs_remove(struct eventfs_file *ef)
struct dentry *dentry_list = NULL;
struct dentry *dentry;
- if (!ef)
+ if (IS_ERR_OR_NULL(ef))
return;
mutex_lock(&eventfs_mutex);
--
2.34.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2] eventfs: Fix the NULL pointer dereference bug in eventfs_remove_rec()
2023-09-09 7:28 [PATCH v2] eventfs: Fix the NULL pointer dereference bug in eventfs_remove_rec() Jinjie Ruan
@ 2023-09-09 9:48 ` Masami Hiramatsu
2023-09-09 10:14 ` Ruan Jinjie
2023-09-09 10:20 ` Ruan Jinjie
0 siblings, 2 replies; 4+ messages in thread
From: Masami Hiramatsu @ 2023-09-09 9:48 UTC (permalink / raw)
To: Jinjie Ruan; +Cc: linux-trace-kernel, Steven Rostedt, Ajay Kaher
On Sat, 9 Sep 2023 15:28:16 +0800
Jinjie Ruan <ruanjinjie@huawei.com> wrote:
> 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, use IS_ERR_OR_NULL() to
> check ef in eventfs_remove_rec(), and fix the same issue
> in eventfs_remove().
>
> 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>
> ---
> v2:
> - Use IS_ERR_OR_NULL() to check instead of IS_ERR() as suggested.
> - Update the commit message.
> ---
> fs/tracefs/event_inode.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
> index 237c6f370ad9..c354b6013881 100644
> --- a/fs/tracefs/event_inode.c
> +++ b/fs/tracefs/event_inode.c
> @@ -693,7 +693,7 @@ static void eventfs_remove_rec(struct eventfs_file *ef, struct list_head *head,
> {
> struct eventfs_file *ef_child;
>
> - if (!ef)
> + if (IS_ERR_OR_NULL(ef))
Sorry, I think `ef` must not be an error value because in between the allocation
and this removing, some code can accidentary access it because it is not NULL.
I think the allocator must set NULL, if it's not, it should be warned.
if (!ef || WARN_ON_ONCE(IS_ERR(ef)))
return;
Of course this still cause a warning, so fix the eventfs_add_dir() too.
(But fixing the eventfs_add_dir() will remove the error, we may not need
this WARN_ON_ONCE() here.)
Or, any other path did you find which sets ef=ERR_PTR(err)?
Thanks,
> return;
> /*
> * Check recursion depth. It should never be greater than 3:
> @@ -730,7 +730,7 @@ void eventfs_remove(struct eventfs_file *ef)
> struct dentry *dentry_list = NULL;
> struct dentry *dentry;
>
> - if (!ef)
> + if (IS_ERR_OR_NULL(ef))
> return;
>
> mutex_lock(&eventfs_mutex);
> --
> 2.34.1
>
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] eventfs: Fix the NULL pointer dereference bug in eventfs_remove_rec()
2023-09-09 9:48 ` Masami Hiramatsu
@ 2023-09-09 10:14 ` Ruan Jinjie
2023-09-09 10:20 ` Ruan Jinjie
1 sibling, 0 replies; 4+ messages in thread
From: Ruan Jinjie @ 2023-09-09 10:14 UTC (permalink / raw)
To: Masami Hiramatsu (Google); +Cc: linux-trace-kernel, Steven Rostedt, Ajay Kaher
On 2023/9/9 17:48, Masami Hiramatsu (Google) wrote:
> On Sat, 9 Sep 2023 15:28:16 +0800
> Jinjie Ruan <ruanjinjie@huawei.com> wrote:
>
>> 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, use IS_ERR_OR_NULL() to
>> check ef in eventfs_remove_rec(), and fix the same issue
>> in eventfs_remove().
>>
>> 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>
>> ---
>> v2:
>> - Use IS_ERR_OR_NULL() to check instead of IS_ERR() as suggested.
>> - Update the commit message.
>> ---
>> fs/tracefs/event_inode.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
>> index 237c6f370ad9..c354b6013881 100644
>> --- a/fs/tracefs/event_inode.c
>> +++ b/fs/tracefs/event_inode.c
>> @@ -693,7 +693,7 @@ static void eventfs_remove_rec(struct eventfs_file *ef, struct list_head *head,
>> {
>> struct eventfs_file *ef_child;
>>
>> - if (!ef)
>> + if (IS_ERR_OR_NULL(ef))
>
> Sorry, I think `ef` must not be an error value because in between the allocation
> and this removing, some code can accidentary access it because it is not NULL.
>
> I think the allocator must set NULL, if it's not, it should be warned.
>
> if (!ef || WARN_ON_ONCE(IS_ERR(ef)))
> return;
>
> Of course this still cause a warning, so fix the eventfs_add_dir() too.
> (But fixing the eventfs_add_dir() will remove the error, we may not need
> this WARN_ON_ONCE() here.)
> Or, any other path did you find which sets ef=ERR_PTR(err)?
Not found so far.
>
> Thanks,
>
>> return;
>> /*
>> * Check recursion depth. It should never be greater than 3:
>> @@ -730,7 +730,7 @@ void eventfs_remove(struct eventfs_file *ef)
>> struct dentry *dentry_list = NULL;
>> struct dentry *dentry;
>>
>> - if (!ef)
>> + if (IS_ERR_OR_NULL(ef))
>> return;
>>
>> mutex_lock(&eventfs_mutex);
>> --
>> 2.34.1
>>
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] eventfs: Fix the NULL pointer dereference bug in eventfs_remove_rec()
2023-09-09 9:48 ` Masami Hiramatsu
2023-09-09 10:14 ` Ruan Jinjie
@ 2023-09-09 10:20 ` Ruan Jinjie
1 sibling, 0 replies; 4+ messages in thread
From: Ruan Jinjie @ 2023-09-09 10:20 UTC (permalink / raw)
To: Masami Hiramatsu (Google); +Cc: linux-trace-kernel, Steven Rostedt, Ajay Kaher
On 2023/9/9 17:48, Masami Hiramatsu (Google) wrote:
> On Sat, 9 Sep 2023 15:28:16 +0800
> Jinjie Ruan <ruanjinjie@huawei.com> wrote:
>
>> 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, use IS_ERR_OR_NULL() to
>> check ef in eventfs_remove_rec(), and fix the same issue
>> in eventfs_remove().
>>
>> 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>
>> ---
>> v2:
>> - Use IS_ERR_OR_NULL() to check instead of IS_ERR() as suggested.
>> - Update the commit message.
>> ---
>> fs/tracefs/event_inode.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
>> index 237c6f370ad9..c354b6013881 100644
>> --- a/fs/tracefs/event_inode.c
>> +++ b/fs/tracefs/event_inode.c
>> @@ -693,7 +693,7 @@ static void eventfs_remove_rec(struct eventfs_file *ef, struct list_head *head,
>> {
>> struct eventfs_file *ef_child;
>>
>> - if (!ef)
>> + if (IS_ERR_OR_NULL(ef))
>
> Sorry, I think `ef` must not be an error value because in between the allocation
> and this removing, some code can accidentary access it because it is not NULL.
>
> I think the allocator must set NULL, if it's not, it should be warned.
>
> if (!ef || WARN_ON_ONCE(IS_ERR(ef)))
> return;
>
> Of course this still cause a warning, so fix the eventfs_add_dir() too.
> (But fixing the eventfs_add_dir() will remove the error, we may not need
> this WARN_ON_ONCE() here.)
I think fixing the eventfs_add_dir() is fine.
> Or, any other path did you find which sets ef=ERR_PTR(err)?
>
> Thanks,
>
>> return;
>> /*
>> * Check recursion depth. It should never be greater than 3:
>> @@ -730,7 +730,7 @@ void eventfs_remove(struct eventfs_file *ef)
>> struct dentry *dentry_list = NULL;
>> struct dentry *dentry;
>>
>> - if (!ef)
>> + if (IS_ERR_OR_NULL(ef))
>> return;
>>
>> mutex_lock(&eventfs_mutex);
>> --
>> 2.34.1
>>
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2023-09-09 10:20 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2023-09-09 7:28 [PATCH v2] eventfs: Fix the NULL pointer dereference bug in eventfs_remove_rec() Jinjie Ruan
2023-09-09 9:48 ` Masami Hiramatsu
2023-09-09 10:14 ` Ruan Jinjie
2023-09-09 10:20 ` Ruan Jinjie
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