diff options
| author | Thomas Gleixner <[email protected]> | 2018-06-22 21:20:35 +0200 |
|---|---|---|
| committer | Thomas Gleixner <[email protected]> | 2018-06-22 21:20:35 +0200 |
| commit | 7731b8bc94e599c9a79e428f3359ff2c34b7576a (patch) | |
| tree | 879f18ccbe274122f2d4f095b43cbc7f953e0ada /kernel/sys.c | |
| parent | 48e315618dc4dc8904182cd221e3d395d5d97005 (diff) | |
| parent | 9ffc59d57228d74809700be6f7ecb1db10292f05 (diff) | |
Merge branch 'linus' into x86/urgent
Required to queue a dependent fix.
Diffstat (limited to 'kernel/sys.c')
| -rw-r--r-- | kernel/sys.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/kernel/sys.c b/kernel/sys.c index d1b2b8d934bb..38509dc1f77b 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2018,7 +2018,11 @@ static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data return error; } - down_write(&mm->mmap_sem); + /* + * arg_lock protects concurent updates but we still need mmap_sem for + * read to exclude races with sys_brk. + */ + down_read(&mm->mmap_sem); /* * We don't validate if these members are pointing to @@ -2032,6 +2036,7 @@ static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data * to any problem in kernel itself */ + spin_lock(&mm->arg_lock); mm->start_code = prctl_map.start_code; mm->end_code = prctl_map.end_code; mm->start_data = prctl_map.start_data; @@ -2043,6 +2048,7 @@ static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data mm->arg_end = prctl_map.arg_end; mm->env_start = prctl_map.env_start; mm->env_end = prctl_map.env_end; + spin_unlock(&mm->arg_lock); /* * Note this update of @saved_auxv is lockless thus @@ -2055,7 +2061,7 @@ static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data if (prctl_map.auxv_size) memcpy(mm->saved_auxv, user_auxv, sizeof(user_auxv)); - up_write(&mm->mmap_sem); + up_read(&mm->mmap_sem); return 0; } #endif /* CONFIG_CHECKPOINT_RESTORE */ |